What is a Shellfish Allergy?
English name: anaphylaxis
Allergy
- Allergy is the most urgent event in clinical immunology. Now described as a group of severe clinical symptoms involving immune or non-immune mechanisms, often sudden, involving multiple target organs, is a clinical syndrome with multiple elicitors and different pathogenic mechanisms. This disease is common in pediatrics, and the overall prevalence of allergies in the normal population ranges from 10% to 60%. The incidence of allergies is basically similar between the sexes, but some reports suggest that women are slightly higher than men. Other statistics show that males have a higher incidence than females, with females accounting for 51% and males 49%.
Basic overview of allergies
- English name: anaphylaxis
- Alias: anaphylactic shock; severe allergic reaction; hypersensitivity; allergicshock; shockanaphylacticus
- When the human body comes into contact or is injected with a special antigen that is not excessive and usually tolerable,
- Allergy
Causes of Allergies
- Food Any food, including Chinese cabbage, can cause allergies, but the most common allergies are milk, egg whites, peanuts and other legumes, nuts and other few foods.
- Avian-related vaccines include measles mumps, yellow fever and influenza vaccines. The main adverse reactions caused by the vaccines are poultry protein in the vaccine and hydrolyzed gelatin, sorbitol and neomycin in some vaccines. Medical history often provides clues.
- Hymenoptera insects such as bees can cause local or systemic allergies in sensitized individuals. Can be a variety of bee venom for skin test diagnosis.
- The most common drugs are -lactam antibiotics, aspirin, and non-steroidal anti-inflammatory drugs.
- Skin tests and IT are very likely to induce allergies because the allergen used is or may be the cause of allergies in children.
- Exercise found a new type of patients. After exercise, wind masses and other allergic symptoms are called exercise-induced anaphylaxis (EIA). Some patients experience exercise after a meal, regardless of the type of food. Others respond to exercise only after eating special foods. It is said that exercise depends on food to induce allergies. The prevention method is not to exercise for 2 hours after a meal.
- Cold can also induce allergies. In the case of cold, it can cause wind and itch, and it disappears quickly after warming. In severe cases, it can induce systemic allergy. Such patients should avoid excessive cold and swimming. Once symptoms occur, they should be as soon as possible. Keep your body warm.
- 99Natural rubber is 99% latex from oak. Diagnosis is based on skin prick test. In vitro detection of latex specific IgE is less sensitive than skin test. There is no latex extract in China, and a rubber product can be used for a rapid patch test for 20 to 30 minutes to observe the results. Latex is a raw material for manufacturing various rubber gloves, medical rubber catheters, anesthesia masks, toy pacifiers and the like. Therefore, any child who develops symptoms after sucking a pacifier, blowing a balloon, playing with rubber toys, or using other latex products should be suspected of being allergic to latex. Those who are allergic to latex are also allergic to a variety of vegetables and fruits.
- 90 90% of allergies during general anesthesia during surgery occur within 3 minutes of intravenous administration, often involving muscle relaxants. Latex allergic reactions usually occur within 20 to 60 minutes. Observation of systemic reactions during 100 cases of anesthesia was as follows: 68% of circulating collapse, 55% of flushing of the skin, 55% of skin edema (mainly involving the face), 23% of bronchial obstruction, and 11% of cardiac arrest. Neuromuscular blocking drugs such as succinylcholine (scholine), opioid painkillers, antibiotics or protamines used during surgery, latex, blood transfusions, and anesthetics are also easily induced.
- Many of the primary recurrent allergies are only temporarily found no cause. Therefore, the diagnosis is mainly to exclude some patients in the test. A severe asthma reaction after a meal may be due to metabisulfite in the food. Other recurrent unexplained shocks may be caused by penicillin in milk and so on.
Pathogenesis of allergies
- Many allergies are IgE-mediated. MC degranulation releases the major mediators histamine and other vasoactive amines, LTs, PG and PAF. Histamine has a short half-life in plasma, but it has been identified as an important mediator of human allergies. As for the mechanism of non-IgE-mediated allergies, it is speculated that the production of allergic toxins C3a and C5a due to complement activation. These molecules can directly increase smooth muscle contraction and increase vascular permeability. Neuropeptides such as SP, vasoactive intestinal peptide (VIP), and somatostatin (SOM) have a strong ability to induce mediator release, especially the ability to stimulate the rapid release of histamine. The mechanisms by which aspirin and nonsteroidal anti-inflammatory agents cause allergic reactions are not fully understood. Mast cell-secreting agents such as opioids are thought to be caused by the rapid release of histamine. But many scholars believe that the sensitivity of the host to the medium is more important.
- The main pathological changes in human lethal allergies include acute pulmonary overexpansion, laryngeal edema, visceral congestion, pulmonary edema, alveolar hemorrhage, urticaria / angioedema but some patients have no pathological changes. Someone has used advanced histopathology to find that 80% of the fatal cases have myocardial damage.
Allergic symptoms and clinical manifestations
Common symptoms of allergies
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Common allergies to allergies
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Clinical manifestations of allergies
- The onset, manifestations, and processes of this syndrome vary, and general symptoms related to the strength of the allergen, the patient's health, and hereditary qualities can begin to occur quickly within seconds and minutes after exposure to the inducer, and can also occur in the After 1h. Some patients have aura before symptoms appear, but these early symptoms such as anxiety and dizziness, patients often can not tell the symptoms are systemic, ranging in severity. Most patients prescribe with skin symptoms
- Allergy
- The above symptoms and signs can be present alone or in combination. Most severe reactions involve respiratory and cardiovascular reactions. People who have lost consciousness can die within minutes, or after a few days or weeks, but generally the later the onset of symptoms of an allergic reaction, the less severe the reaction. Late reactions may occur again 4-8 hours after the early allergic reactions have dissipated.
- Allergies can be caused by any route including oral, intravenous, dermal, topical, inhalation and mucosal contact. Severe cases of adults are prone to induce shock, while children are more likely to involve the respiratory tract. Therefore, severe cases should be particularly alert to respiratory symptoms. If the patient has an airway obstruction, the chest X-ray may show excessive lung inflation and / or atelectasis. If the patient has shock, due to a large amount of exudation, blood concentration can be seen. Occasionally, there may be signs of myocardial ischemia or injury.
- Complications: Severe cases can occur: shock, laryngeal edema, suffocation, arrhythmia, myocardial ischemia, cardiac arrest, loss of convulsions, and multiple organ failure.
Clinical diagnosis of allergies
- Sudden collapse without urticaria and angioedema often occurs after injection or pain. The patient is pale and complains of nausea, but before syncope, the skin does not itch, no cyanosis occurs, and there is no dyspnea. The symptoms are almost flat Immediately improved, there may be a lot of sweating and slow pulse.
- Dyspnea and prostration caused by excessive ventilation, but it is generally not accompanied by other symptoms and signs, and blood pressure and pulse are normal except for numbness in the body and around the mouth.
- Mental factors are more common in teenage girls. Most of the symptoms can be controlled by will, and can be repeated when prompted. Physical examination and laboratory tests are normal. For these patients, the first step is to eliminate the disease. Patients are then encouraged to correct.
Allergy test method
Allergy laboratory test
- Non-specific diagnosis is: eosinophil examination of blood, sputum, nasal discharge, stool, middle ear secretion, etc .; determination of histamine content in blood, other body fluids or secretions; IgE in serum and secretions, Determination of IgA, IgG, IgM content; Pulmonary function measurement; T lymphocyte transformation test; Complement Ch50, Ch2, C3, C4 measurement; Macrophage migration inhibition test; Measurement of leukocyte phagocytic index; 17 ketones, 17 hydroxyl in blood and urine Steroid determination; Plasma protein electrophoresis determination; Erythrocyte sedimentation test; Blood anti-hemolytic streptococcal antibody titer determination; Rheumatoid factor determination; Antigen-antibody complex determination; Blood lupus erythematosus cell examination; Routine examination of hematuria, stool, etc. . These detection methods have their own diagnostic significance for different allergic diseases and can be chosen to use.
- In vivo specific diagnosis The most extensive in vivo specific diagnosis method is used in clinical allergies. The skin test method is the first to be used. In addition, there are a variety of test methods other than skin, including nasal mucosa, bronchial mucosa, eye conjunctiva, and oral mucosa tests. .
- The principle of in-vivo specific diagnosis is: a specific antibody is contained in the skin and body fluids of exogenous allergic patients, which is called reactin or skin-sensitive antibody, that is, specific IgE. When the corresponding antigen enters the skin through different pathways, that is, it combines with reptin, releases the allergic active medium, produces a local allergic reaction, makes the skin congested, edema, and exudation to form pimples, and erythema appears around the pimples. This is the specificity. Positive skin test. Because the amount and concentration of antigen entering the skin are strictly controlled, this test method is relatively safe. The reaction occurs only locally but there are very few highly sensitive patients. Even under strict control of antigen concentration and dose, a strong systemic reaction can occur, and even anaphylactic shock has been caused by skin tests. Such as the death of shock caused by penicillin skin test has occurred. Hundreds of thousands of people have used specific skin tests, and there has been no case of a fatal reaction caused by a skin test. Occasionally, those who have responded to asthma attacks or urticaria due to specific skin tests can be promptly controlled after appropriate treatment. This shows that the methods used, such as strict mastery of operating procedures, and making necessary emergency preparations are generally safe.
- Indications for specific diagnosis in vivo: Patients with rapid-onset exogenous allergies or patients with contact allergies in delayed allergies. The patient should not be in the period of intense allergy during the test. No corticosteroids, antihistamines, epinephrine or other similar drugs have been used. The skin of the patient's test site is not in a state of strong non-specific irritability. Such patients, such as obvious skin scratches, are prone to false-positive reactions when subjected to skin tests. The skin of the patient's test site should be free of eczema, urticaria or other skin damage.
- The types and methods of specific diagnosis in vivo: patch test: This is an older method, also known as patch test. As early as 1896, Swiss dermatologist Jadasson created this method to investigate the cause of sensitization in patients with suspected drug allergies. This is a fairly simple and secure method that is still used today. The specific method of the test is: for suspected allergic drugs, food or inhalants, if it is a solid substance, first grind it into fines or crush it, then take a small amount and place it on the ventral skin of the patient's forearm, and then place a drop of 0.1mol / L sodium hydroxide solution or physiological saline gently mix the powder with water, wait for it to dry, cover it with a piece of cellophane or plastic film that does not absorb water, and then wrap with gauze to keep the test object in close contact with the skin for 24 to 48 hours and then remove it. For dressing, observe whether the skin in contact with the test object is swollen, rash, itchy, or ulcerated. If the above situation is a positive reaction. If the skin was mildly swollen, rash, and itchy, it was a positive reaction. If there is a scattered small rash, the obvious itch is a second positive reaction. If a patch of rash or herpes appears, it is a third-degree positive reaction. If skin exudation, ulcer and necrosis occur, it is a fourth degree positive reaction. If no special skin changes have been seen when the dressing is uncovered at 48h, the contact time can be extended for another 24h, and the patch should be observed again after 72h. In this case, no skin reaction is a negative reaction. When performing patch tests on cloth artificial fibers and other solid suspected contact allergens, the use of simulated artificial sweat as a wetting agent for patching is more similar to the onset of allergens when applying 0.1mol / L sodium hydroxide or normal saline. The natural contact and absorption state has better effect. The formula of artificial sweat is: 3 g of sodium chloride, 1 g of 2 ml of lactic acid, 1 g of sodium sulfate, 2 ml of urea, and 2 ml of stearic acid. Distilled water is added to make the total amount 1L.
- For contacting allergens in the original liquid state, it can be directly applied on the skin surface and then bandaged. Observe the results of the patch test. In addition to observing the immediate response after the patch is peeled off from 24 to 48 hours, you should also check whether the local skin has a delayed positive reaction 12 to 24 hours after the patch is removed. The disadvantage of the patch test is that many test allergens cannot be absorbed by the skin, so they often give false negative results. Conversely, there are some allergic principles that have certain non-specific irritation to the skin and may cause false positive reactions. Moreover, the variety tested each time is limited and the observation time is longer. For some patients with a strong positive reaction, the dressing should be removed early, and it is not necessary to wait for 24 hours or 48 hours, so as not to cause the patient's pain due to excessive response. People also use plastic aluminum film blister packs for packaging pills to clean and dry them, cut them into caps and put them in a small cap in the cap for later use. Then use the allergen solution for the test A dropper is dropped on the cotton swab, and then this small cap is buckled on the skin on the ventral surface of the forearm. In addition, a small cap was dropped on the forearm while using physiological saline as a control, and the small cap was fixed with adhesive tape. The small cap was peeled off at 24h and 48h to observe the skin reaction. In addition, a commercially available band-aid bandage can be used to remove a gauze sheet containing Ravennor in the center and replace it with a multi-layer clean white gauze. Drop the antigen solution to be tested on the gauze and seal it on the skin of the forearm. Open the observation reaction at regular intervals. The above method is stable in sealing, easy to obtain materials, easy to operate, and can be tried. Some hospitals also have cup-shaped patch caps made of thin aluminum sheet to prepare skin patch testers. The patch test is most suitable for contact allergies. In fact, this method can be regarded as a skin challenge test for contact allergies. Cosmetic allergies, chemical agent allergies, and many occupational allergies are related to skin contact, so the adaptability of the test is wide. The current difficulty is how to determine the optimal concentration of the test antigen is a key issue. The concentration is too low to cause false negative reactions. Excessive concentrations can cause false positive reactions. The International and North American Contact Dermatitis Research Group has studied the optimal patch concentration for reference of a few chemicals, and some manufacturers have made this ointment for patch test.
- scratch test: This is also a relatively simple and safe method. Because it does not require disinfection or special equipment during the test, it does not cause local pain or bleeding, and the result is more accurate and faster than the patch test, so it is more suitable for children. . The test can be performed on the outer skin of the patient's forearm. In infants, the area within the shoulder blades on both sides of the back can be used because the skin area available on the arms is too small. Operation method: use a blunt edge ophthalmic cataract knife or use a laboratory blood collection needle, if necessary, use ordinary quilting needles or injection needles instead of people using commercially available acupuncture doctors The triangular prism needle, because of its thick and long handle, moderate tip size is easy to hold and not easy to damage, it is recommended to hold the needle on the selected skin surface in the test first, and draw two parallel longitudinal lengths of 3 to 5 mm. -Shaped scratches, there are also cross-shaped cross-shaped or X-shaped. If the test substance is powdery, the principle of allergy is to first drop a drop of 0.1mol / L sodium hydroxide physiological saline or artificial Sweat, then use a clean metal spoon to take the antigen and a small spoon to sprinkle on the liquid. Use a commercially available aluminum ear spoon, which is cheap and applicable. The round end of the ear spoon is available. Stir in. If the test is a liquid antigen, put a drop of antigen on the scratch and wait for it to dry naturally. After the antigen has contacted the skin scratch for 15-20 minutes, the reaction can be observed. Judgment of scratch test results often has its own experience and standards. The standard people commonly use is: A. The skin is slightly bulged at the scratch, and there is a light red spot around the scratch (+); B. The pimples-like bulge at the scratch is longer than the range of the scratch, and there are obvious red spots around the pimples Is (++); C. The pimples at the scratches have pseudopodia, and the erythema responders with wide, reddish and irregular edges around the scratches are (+++); D. The pimples at the scratches have more than 2 pseudo Feet, itching, and obvious redness and swelling around the skin are (++++).
- Note for scratch test: If multiple antigen tests are performed at the same time, the test sequence and location of each antigen must be clearly remembered; if necessary, marks should be made on the skin to avoid confusion. If a skin test is performed with multiple antigens grouped, the order of each antigen should be memorized. If the test is performed on the outer skin of the upper arm, the arrangement procedure of the antigen is customarily from top to bottom, from left to right, each line is 5 lines, each arm is divided into 2 lines inside and outside, 10 types can be made in total, both arms At the same time can be used for skin tests of 20 antigens. For example, if the back of the interscapular skin is used for the test, if the test subject is an adult, 10 types can be tested from top to bottom, and 6 lines can be tested from left to right, so a skin test of 60 antigens can be performed at the same time.
- For the test, the needles and spoons used in the scratch should be prepared in dozens to hundreds of sets, and used up and discarded to prevent antigens from mixing. Cross-reaction The distance between the upper, lower, left and right sides of each test, at least 3 to 5 cm. It is not necessary to sterilize the skin with alcohol to avoid congestive reactions caused by alcohol to interfere with observation results. For individual patients whose skin is too dirty, they can be washed with water and soap first, and then tested after drying. If a strong reaction has occurred in the endothelial test area 15 minutes after the test, the antigen can be wiped off with cotton dipped in distilled water to prevent further development of the reaction.
- prick test: also known as puncture or puncture test (puncture test), this method is actually a modification of the scratch test. Because the method is simple and convenient, many foreign allergies have adopted this method. The method is to apply a drop of antigen to the skin test site, and then use a special puncture needle to puncture the center of the skin with the antigen, press the needle tip to about 1mm inside the skin, and then gently lift the epithelium away. Too deep, not to bleed. Some people also use 16 or 17 flat-tipped needles (such as the needle used for the injection of contrast agent during parotid duct angiography) for prick tests. When using it, first put the needle into the antigen bottle, so that the needle tube is filled with a small amount of antigen solution, and then press the needle to puncture the patient's skin with satisfactory results.
- People also use small glass tubes with a diameter of 3mm sawn into small sections for piercing tests. The advantages are that the wall of the tube is smooth, easy to clean, not rusty, less polluting, and cheap; if you use this for a skin test for a child, it will not cause the child to panic. Due to the low price of glass tubes, some can be discarded after each use, and no longer need to be disinfected and reused. Care should be taken to prevent the glass tube from breaking during the test. The observation standards and precautions for the prick test are roughly the same as those for the scratch test. With the popularization of piercing tests, disposable stainless steel piercing needles with different shapes have been manufactured for use at home and abroad. It is very convenient to discard after use. The depth of the needle is limited by the shoulder of the needle handle, which can control uniformity. Prick tests are used more widely abroad than in North America.
- Since the 1980s, the puncture test has been increasingly popular, and the puncture equipment has also been improved. In the United States, a plastic puncture device called Multitest has been designed. It is divided into two rows with 4 puncture needles in each row. The needle is brush-shaped. And equipped with 8 commonly used allergen test solution. Eight kinds of allergens were dripped on eight puncture needles during operation. It can be pressed on the ventral skin of the patient's forearm, and a single prick can be used to test 8 allergens at the same time. Italy has also designed a plastic piercing device that can be used for 32 different allergen tests at the same time. The piercing needle is conical, and the tail of the needle has a thick "shoulder" to control the depth of the needle. It's the Priller tester.
- The Pharmacia company in Sweden coated various allergens on stainless steel puncture needles to sterilize and seal the packages separately. For testing, just open the package and remove the puncture needles to puncture directly on the patient's skin without using any liquid. Allergens. This kind of prick test is called "dry prick test", which is very convenient. It has the advantage that the antigen is in a dry state and it is not easy to degrade, so the effective period of use can be increased to 3 years. Single use, no risk of antigen crossover or operation contamination, and both negative and positive controls are available. Because the puncture test operation is simpler and safer than the intradermal test. It is more suitable for children, and some areas have replaced intradermal testing.
- intradermal test (intradermaltest or intracutaneoustest): This is the most widely used in a variety of in vivo specific tests, the results are more reliable test and stricter dose control. People have mainly used this method in clinical practice for specific allergen testing for many years. It can be used to test food, inhalants, certain drugs and insect venom, and its operation method is as follows:
- Generally, the skin on the outer side of the upper arm is also used as the test area. The patient is seated on the side and the entire arm is exposed to 70% alcohol to disinfect the skin. The test solution is extracted with a tuberculin syringe and a 26 or 27 gauge intradermal needle with a needle length of about 1 cm. Disposable syringes have been widely adopted in the West. China is also gradually promoting disposable syringes. For safety reasons, it will soon be popularized in China. The concentration of the test solution varies according to their experience. People use inhaled antigens, including house dust, feathers, old cotton wool, tobacco, fungi, pollen, etc., with a concentration of 1: 100. For food antigens that do not contain irritating vegetables, fruits, grains, etc., use a 1:10 concentration. For fish, shrimp, crab, eggs, milk and onions, garlic, ginger, pepper and other high-protein foods or irritating foods, 1: 100 concentration is used. For individual strong titers, such as Artemisia pollen, mites, etc., people use a concentration of 1: 1000 or 1: 10,000. There are also some highly potent antigens, such as tapeworm infusions. People have used concentrations of 1: 100,000 each. Allergic clinicians must have an approximate potency for the various antigens they use. Know so that you have the appropriate test concentration to prevent adverse reactions or accidents.
- The test follows the customary procedure, from top to bottom, one by one from left to right. In each test area, use an intradermal needle to pierce the superficial layer of the epidermis, and then insert the needle about 2 to 3 mm, and push about 0.01 to 0.02 ml of test solution each. The test area should be at least 3 cm apart. The reaction results can be observed 15 minutes after the skin test. The determination criteria of the response results are as follows: A. The subject's skin pimples are less than 5mm in diameter, no erythema is formed around them, or those with only mild erythema are negative; Light erythema reaction between 5-10mm, (+); C. Skin pimples between 10-15mm in diameter, and erythema reaction bands with a width of more than 10mm, (++); D. Skin Those with pimples more than 15mm in diameter or irregular pimples with erythema response bands with a width of more than 10mm around the pseudofoot are (+++); E. Local reactions are the same as (+++), and there are also whole body reactions at the same time, such as Itchy skin rash, rash, skin flushing, gas, asthma and other symptoms are (++++).
- In the intradermal test, the disinfection of needles and needles should be paid attention to, and the names and concentrations of the antigens should be marked on the needles to prevent mutual contamination. In the allergy specialist clinic, intradermal tests are performed for a large number of patients every day, so multiple metal syringe boxes should be prepared, and the syringes containing various antigens should be filled in sequence after sterilization. Intradermal needles for injection should also be prepared in large quantities and should be replaced once. Syringes do not have to be replaced once per person. After each clinic, the intradermal needles should be checked one by one for barbs and dullness. If barbs or dullness are found, they should be sharpened at any time to ensure the next check.
- After the skin test injection is completed, within 15 to 20 minutes of waiting for the patient to observe the response, the patient should be observed at any time for systemic reactions such as lip numbness, palm itching, general itching, flushing of skin color, cough and asthma, chest tightness, pulse rate, etc. Happening. In such cases, the patient should immediately lie down and rest, and appropriate measures should be given according to the severity of the reaction. The lighter can acupuncture the palm of the patient or acupuncture points in the middle, Yintang, and Shixuan. Those who have chest tightness, cough and asthma are inhaled with drugs such as isoproterenol or salbutamol (shuchuanling). Severe cases should be injected with epinephrine, oxygen, or even artificial respiration by intravenous injection of epinephrine. For more than 20 years, people have carried out intradermal tests on hundreds of thousands of patients, although several cases of heavier skin have occurred. After the test, all of them recovered safely due to timely processing.
- Acupuncture of palms and palms was performed on patients who had a systemic reaction after a skin test and received very good results. The method is to use a 1.5-inch (1.5-inch = 3.3cm) acupuncture needle to pierce the center of the palm of the patient on both sides and insert the needle for about 1 inch, twist it a little, and leave the needle for about 10 minutes. Generally, the situation will gradually appear 3 to 5 minutes after the needle. restore. In addition, aerosol inhalation of isoproterenol, salbutamol (shuchuanling), terbutaline (chuankangsu) is also effective for patients with asthma attacks after skin tests. Therefore, sterilized acupuncture and acupuncture needle isoproterenol Shuchuanling aerosol, as well as epinephrine and ephedrine (ephedrine) for injection should also be prepared at any time in the clinic, in order to prevent the occurrence of whole body sexual reactions after skin tests.
- Intradermal test should also prevent local infection. In addition to strict aseptic technique during operation, check the skin test antigen for contamination at any time. Because repeated aspiration of the antigen in the bottle with a needle can bring in contaminants over time. Therefore, pay attention to observe whether the drug solution is turbid or precipitated each time you draw the medicine. Usually, the antigen should be stored in a refrigerator at about 4 ° C. The prepared skin test antigen should be reconstituted and updated after 1 month of use.
- Work closely with doctors, nurses, or technicians working in the allergy clinic. Skin tests are generally performed by nurses or technicians, and if special conditions occur during the test, they should be reported to the doctors to cooperate and take measures at any time. During the collection of medical history or examination, if the doctor finds that the patient has a strong allergic reaction to something, he should also remind the skin tester to pay attention to the skin test. If necessary, he can use a higher dilution of the antigen for the skin test. Before skin test, make patch test or scratch test for safety.
- In the intradermal test, the injection of air into the skin should be prevented; once injected, local skin may have a false positive reaction. The false-positive skin reaction caused by the injection of air can sometimes be a "splatter phenomenon", because after the injection of air, it can disperse into a large number of small air bubbles and migrate to the intradermal tissues, causing scattered red spots on the skin, which is similar to the injection of antigen. The flaky reactions that appear are different and can be distinguished from the true positive reactions described earlier by careful observation. Intradermal test injection should avoid blood vessels. After the needle is inserted, blood should be withdrawn before the drug can be pushed to prevent the test solution from directly entering the blood vessels and causing a strong reaction.
- In general, after the skin test of the entire group of antigens is completed, an intradermal control test with normal saline or a vehicle for extracting the antigen should be performed in the vicinity to rule out the possibility of false positive reactions caused by non-specific stimulation. At the same time, a 0.1 mg / ml histamine phosphate solution was also used as a positive control test to rule out possible false negative reactions. During the skin test in winter, patients should be kept warm to prevent colds and colds.
- When performing intradermal tests for patients in the allergy clinic, a large number of tuberculin syringes are used daily. The barrel and core of each syringe should be numbered, and they should be performed one by one to prevent the barrel and core from being paired. As a result, liquid leakage or the cartridge core cannot be inserted into the tube.
- Conjunctival test: As the bulbous conjunctiva and eyelid conjunctiva have rich and regularly arranged capillary networks, the background of the eye conjunctiva is extremely bright and clean. It is a good place to observe the antigen-antibody reaction, and The response is very fast, so in some cases, the eye conjunctiva can be used for allergen-specific tests. The method is as follows: firstly, a drop of 1: 1000 antigen is dripped into the right eye of the patient. If no itching, redness, tearing, conjunctival congestion and the like occur after 5 minutes, a drop of 1: 100 antigen may be added and then observed for 5 minutes. If there is still no response, add 1 drop of 1:10 antigen if necessary. If there is still no response, it is negative. If the eye drops red, itching, tearing, conjunctival congestion, or even eyelid edema after the instillation of the antigen, it is a positive reaction. As a control, one drop of physiological saline or antigen extraction vehicle can be added to the left eye at the same time. The positive reaction was graded as follows: mild sclera and conjunctival hyperemia (+); sclera and conjunctival hyperemia, mild itching (++); sclera and conjunctival all red, obvious itching and tearing (+++); (+++) On the basis of conjunctival hemorrhage, eyelid edema, etc. (++++).
- The advantage of this method is that the rapid response is clear and vivid. This test can also be performed on allergies to certain suspicious liquids. However, it has the following disadvantages: all stimulating antigens are not suitable for this method. Only one type of antigen can be tested at a time. It is not appropriate to perform multiple antigen tests.
- Nasal mucosa provocation test (nasalmucosaprovocationtest): The test can be divided into two types, one is the antigen inhalation test (inhalationtest), that is, inhalation of antigen from the nose to stimulate the symptoms of allergic rhinitis. Many clinical tests have been performed on some patients with a typical history of hay fever allergies and negative intradermal tests, and it has been found that more than half of them can induce different degrees of hay fever symptoms. The operation method is: put a very small amount of dried pollen into the nasal cavity of the patient, and after a few minutes, the patient will develop paroxysmal sneeze, runny nose, nasal congestion, and itchy nose. Examination showed pale and edema of the nasal mucosa, and a large increase in secretions. Some patients have asthma attacks at the same time. At this time, a large number of eosinophils can be detected from the patient's nasal secretions or sputum.
- The trial was lively and very convincing to both patients and doctors. The disadvantage is that only one antigen can be tested at a time. The dose of challenge antigen should be strictly controlled to prevent the occurrence of strong reactions. In such trials, asthmatics are induced, but after proper treatment, wheezing subsides. The other is an intranasal instillation test. Various inhaled antigen infusions can be dripped intranasally to test their sensitivity. In clinical practice, people have also tried some pollen infusion nasal drip stimulation tests and found that the positive rate is far lower than that of dry pollen inhalation challenge. In addition, the test antigen infusion can be dropped on a 1.0cm × 1.0cm square white filter paper and then the paper is applied to the inferior turbinate mucosa of one side of the nasal cavity for excitation, but the reaction intensity is far less obvious than that of direct pollen stimulation.
- (3) Bronchialprovocative test: Similar to the nasal mucosa provocation test, antigen aerosol inhalation challenge or antigen infusion trachea instillation challenge can be used. Some people also use aerosol inhalation or instillation of histamine in the trachea to carry out non-specific challenge tests to determine the bronchial reactivity of patients. However, the method of inhalation or instillation of histamine or acetylcholine is still controversial. Some people think that even normal people can induce asthma by inhaling or instilling the above-mentioned drugs. The normal evoked dose is different for patients of different ages, genders and weights. As for the intratracheal inhalation or instillation challenge test of the antigen, it has attracted much attention from abroad, and a special instrument has been developed to perform precise quantitative control combined with the measurement of lung function to determine the sensitivity of the patient's bronchus to various specific antigens.
- iontophoresis test: The iontophoresis device is used to ionize the antigen and penetrate it into the skin or other surface tissue of the patient to observe the patient's specific response. The prerequisite for this test is that the antigen must be ionizable Material, and first understand whether the antigen is ionized or free after being ionized, in order to select different electrodes for penetration and also require that the antigen ionization does not affect its antigen titer. Its advantage is painless but complicated to operate. It requires a special set of equipment and there are many links that may affect its results, so it is difficult to promote. Used only for certain experimental studies.
- Sublingual test: Because there are abundant blood vessels under the tongue and the mucous membrane is thin, if you use various foods, inhaled antigen infusions or soluble drugs under the tongue, it can be absorbed within a short period of time and produce corresponding allergic symptoms. The disadvantage is that the scale between the safe dose and the effective dose is difficult to control; only one antigen test can be performed at a time; patients should stop eating similar foods 24h before the test when conducting a food test. The positive response of the sublingual test is often not expressed in the sublingual area but in the respiratory, digestive, and circulatory systems. Therefore, it must be carefully observed by an experienced tester to determine. The founder of the sublingual test, American allergist G. Pfeiffer, has been using this method clinically for patients with a specific diagnosis of allergies for decades.
- foodprovocationtest: This kind of test is suitable for patients who have a history of allergies to a certain food, but whose results are not consistent with the medical history after specific skin tests. In order to further clarify the patient's sensitivity to this type of food, this test can be tried. The method is as follows: Patients are prohibited from using such foods 24h before the test. It is best to fast on the day before the test or only eat a small amount of ordinary diet. Before the test, test the patient's pulse, blood pressure, breathing and white blood cell count, and then let the patient eat suspicious food. The amount of food can be determined according to the disease. Eggs; half a pound of milk can be consumed at a time for people allergic to milk. Then leave the patient in the hospital for observation for about 3h. In the meantime, the pulse, respiration, blood pressure, and white blood cell count were measured at 0.5 and 1.52.5 h after eating. Observe whether the breathing, pulse increased significantly, and blood pressure or white blood cell count decreased. At the same time, observe whether the patients have abdominal pain, nausea, vomiting, rash, itching, diarrhea, headache, sneezing, asthma and other allergic symptoms and record them one by one. If the patient has the corresponding allergic symptoms within 3 hours after eating, and the breathing pulse is significantly faster, or the total number of white blood cells is less than 1000 before the challenge, this is a positive reaction. This test is also known as the leukopenia index test. For such tests, dozens of cases have been done in some patients, but many patients have no special response after the test. Patients should come to the hospital for follow-up visits the next day to observe whether there is a late reaction. The disadvantage of this test is that the procedures are complicated. Only one or two patients can be tested in each clinic, and each patient can only have one food test. However, if there are obvious positive stimulating symptoms in the test, its true significance and vividness in the specific diagnosis of food allergy cannot be denied. If conditions permit, the various specific challenge tests listed above should be carried out in the ward for continuous observation and safety.
- Passive transfer test (passive transfer test): also known as the Prausnitz Küstner test (PK test). This was developed by taking advantage of the fact that the specific circulating antibodies of allergic patients can be passively transferred in serum, and it is the first successful example of in vitro allergen-specific diagnosis in humans in human history. Suitable for young infants who cannot perform specific skin tests in themselves, patients with severe exfoliative dermatitis, restless patients who cannot accept skin tests, patients with severe artificial urticaria who have widespread false-positive skin reactions, other severe skin diseases or severe patients Cannot provide their own skin test. Appropriate volunteer subjects should be selected before the trial, which is generally borne by the patient's parents or relatives. Before the test, a serological examination of the patient about infectious hepatitis or other diseases that may be transmitted by the serum should be performed to prove that there is no infectious disease listed above. Such patients can not be used for 24 hours before the test. Or antihistamines. During the test, 10 ml of blood was collected from the patient and placed in a sterile test tube for centrifugation or standing for 24 hours to isolate the serum. Under aseptic operation, the separated serum was injected intradermally in the back of volunteer subjects according to the number of antigens to be tested, and then injected intradermally in multiple points. 0.1 ml of serum was injected at each place, and a circle was marked with a pen at the injection place. After 24 to 48 hours, specific antigens of various antigens were tested at the serum transfer site in the circle according to the intradermal test method. Volunteer subjects should not be exposed to large amounts of inhalants or foods to be tested before the test. The test results are determined according to the general intradermal test method. It has also been reported that primates such as monkeys and orangutans are used as subjects. The PK test provides a strong basis for the objective existence of specific antibodies for allergic diseases. It is a great contribution to the theoretical study of allergies. In clinical practice, people think that it also has certain application value.
- Specific bacterial vaccine test (specificbacterialvaccinetest): people on a part of the long-lasting bronchial asthma and allergic rhinitis or allergic sinusitis patients explore the respiratory bacterial allergy. Carry out the respiratory bacterial culture and vaccine preparation for the patient, and then use the obtained vaccine to conduct skin test for the patient. Generally, vaccines containing 500 million dead bacteria per ml are diluted by 1: 10001: 100 and 1:10, and then Intradermal tests were performed for patients. Observe the immediate response at 15 minutes and then observe the delayed response at 24 and 48 hours. It was found that the immediate response was not obvious in most patients, and there were individual (+) or (++) positive reactions in the delayed response within 24 to 48 hours; however, rare (+++) reactions were rare. At one time, 9 kinds of catarrhal bacteria, streptococcus aureus, staphylococcus aureus, staphylococcus aureus, pseudomonas aeruginosa, pneumococcus influenzae, proteus, and escherichia coli from the respiratory tract allergies The obtained strains were made into mixed vaccines. As a routine intradermal test item, an intradermal test was performed for patients with respiratory allergies, and the positive rate was not high. However, the use of bacterial antigens for specific skin tests has a long history as a specific diagnosis of bacterial infectious diseases. The most commonly used in clinical practice is the tuberculin test. As a specific diagnosis of tuberculosis infection, it has an important value so far; its degree of positive reaction can be regarded as an important indicator for judging cellular immune function.
- According to the in vivo specific diagnosis methods of the various allergies listed above, it is shown that the specific diagnosis of allergies has developed into a series of very meaningful diagnostic methods with important theoretical and clinical practical value. On the other hand, the accuracy of in vivo specific diagnosis is still limited, and false positive and false negative results still occur in clinical trials. There is still a certain gap between the agreement between the test results and the subjective incentives. Therefore, when performing a specific skin test to make a specific diagnosis, a comprehensive and comprehensive analysis and investigation must be combined with the history, time, place of onset, patient work or occupation characteristics, and objective signs to make a more accurate analysis. in conclusion.
Other auxiliary tests for allergies
- Radiological diagnosis includes chest fluoroscopy, radiography, bronchography, paranasal sinus radiography, and gastrointestinal radiography. It also has important diagnostic significance for certain allergic diseases. Especially for the diagnosis of allergic pneumonia and allergic sinusitis, X-ray examination has a special important value. In addition, X-ray examination helps to identify other non-allergic diseases and exclude complications. Modern imaging diagnosis includes: B-mode CT, magnetic resonance, etc., and is also applied to metamorphosis when necessary
Aided diagnosis of allergic reactions
- Diagnosis of medicaments For certain allergic diseases that cannot be confirmed after various tests, certain drugs that are good for allergies can also be used, such as epinephrine, 2 receptor stimulants, and various antihistamine , A variety of adrenocortical drugs, etc., for tentative treatment. If the effect of the drug is outstanding, the diagnosis of allergic diseases can be cited from the side. However, in the diagnosis of such tentative drugs, the condition must be comprehensively considered, and the contraindications and possible side effects of the tested drugs on patients must be ruled out.
Allergy Treatment Approach
- Because death can occur within a few minutes, rapid management is extremely important. The later the treatment is started, the higher the mortality rate. The key to starting treatment is to maintain an open airway and maintain effective blood circulation.
- General treatment: Remove or discontinue the cause or inducer of the symptoms as soon as possible; those with hypotension should take the head and feet high; if necessary, inhale oxygen and use bronchodilators. To remove their tension and fear emotionally
- Application of medicines: First, inject subcutaneously 1: 1000 epinephrine in children, at a rate of 0.01ml / kg, the maximum amount is 0.3ml, if needed, the interval should be 15 ~ 30min. Adrenaline works quickly and is the first choice for allergy first aid. Followed by antihistamines and corticosteroids. But they are not the drugs of choice for first aid. If the condition is severe, intravenous fluids can be infused as soon as possible to replenish fluid that has leaked from the blood vessels into the tissues to treat shock and correct acidosis. This is also a very important part of first aid. After 2 to 4 hours of observation, the patient's symptoms have subsided and he can go home, but he should still observe closely. It is better to observe as long as possible in the medical unit
- Provides effective initial management of all systemic reactions. Early recognition of systemic reactions and the rapid use of epinephrine are vital parts of the treatment. After the initial treatment of the patient has improved, he should be sent to a place where conditions permit to continue treatment. If the symptoms persist or worsen, other measures should be taken on site. Depending on the situation, immediately consult the relevant department for consultation and participate in the rescue together. In short, first aid must be counted every second.
Allergy treatment
- Because death can occur within a few minutes, it is extremely important to respond quickly.
- Anaphylactic shock first aid procedure
- General treatment: Remove or discontinue the cause or inducer of the symptoms as soon as possible; those with hypotension should take the head and feet high; if necessary, inhale oxygen and use bronchodilators. To remove their tension and fear emotionally
- Application of medicines: First, subcutaneously inject 1: 1000 epinephrine in children, at 0.01ml / kg, the maximum amount is 0.3ml, if needed, the interval should be 15 ~ 30min. Adrenaline works quickly and is the first choice for allergy first aid. Followed by antihistamines and corticosteroids. But they are not the drugs of choice for first aid. If the condition is severe, intravenous fluids can be infused as soon as possible to replenish fluid that has leaked from the blood vessels into the tissues to treat shock and correct acidosis. This is also a very important part of first aid. After 2 to 4 hours of observation, the patient's symptoms have subsided and he can go home, but he should still observe closely. Observe as long as possible in the medical unit to provide effective initial treatment for all systemic reactions. Early recognition of systemic reactions and the rapid use of epinephrine are vital parts of the treatment. After the initial treatment of the patient has improved, he should be sent to a place where conditions permit to continue treatment. If the symptoms persist or worsen, other measures should be taken on site. Depending on the situation, immediately consult the relevant department for consultation and participate in the rescue together. In short, first aid must be counted every second.
Allergy prevention
Allergic prognosis
- Generally speaking, the later the symptoms start after antigen stimulation, the less severe, the faster the recovery can be recovered within hours, sometimes it takes several days, and usually complete recovery. If myocardial infarction has occurred, close monitoring is required, but the earlier the treatment is rare in children, the better the prognosis. Therefore, prevention and early timely treatment are extremely important.
Allergy prevention
- Because the disease can be life-threatening, prevention is important. Taking an accurate and complete medical history is important not only for diagnosis but also for prevention. Find out the rules and causes of previous allergic reactions, find out the elicitors, especially potential elicitors and their cross-reactants, and avoid exposure. In addition, most drug-induced allergies cannot be diagnosed by skin tests when suspected need to take medicine The type should be as small as possible, which is conducive to the diagnosis and prevention of systemic allergic reactions during the course of immunotherapy. It should be reduced as appropriate, and patients who have experienced severe allergic reactions at any time during the subsequent injections should have at least 20 minutes. For allergic reactions, a first-aid kit should be prepared, which contains a 1: 1000 adrenaline syringe and 2 inhaler for emergency applications.
Allergy Health
- Allergies, prevention is better than cure. It should start with paying attention to daily living, proper diet and proper physical exercise. First of all, in the early spring season, the temperature is still cold. Under the stimulation of cold air, the thyroid function is hyperactive, consumes calories, and weakens the body's endurance and resistance. Therefore, the diet is still high in calories. In addition to eating soy products, you can also eat glutinous rice products, soybeans, sesame powder, peanuts, walnuts and other foods. You must also add high-quality protein such as eggs, shrimp, and fish. , Beef and other foods, these foods are rich in amino acids, which can increase the body's cold resistance. In addition, you must ingest enough multivitamins and minerals. For example, vitamin C has antiviral ability. Foods rich in vitamin C include cabbage, tomato vegetables, and fruits such as citrus and lemon. Vitamin A can protect and enhance The function of upper respiratory tract mucosa and respiratory tract epithelium cells can resist the invasion of various pathogenic factors. Foods rich in vitamin A include carrots. Vitamin E has the function of improving the body's immune function and enhancing disease resistance. Foods rich in vitamin E include cabbage, cauliflower, and sesame. In addition, black fungus and mushrooms are also indispensable food. There is also the need to have appropriate outdoor activities to improve the body's disease resistance, which is of great benefit in preventing spring allergies.