What Are the Different Types of Rash Ointment?

Allergic rash, a skin disease. Allergic rash is more common than drug allergy, especially in children, and sometimes it is diagnosed as eczema. Common symptoms are abdominal pain, crying, and no vomiting.

Allergic rash

Allergic rash, a skin disease. Allergic rash is more common than drug allergy, especially in children, and sometimes it is diagnosed as eczema. Common symptoms are abdominal pain, crying, and no vomiting.

nickname

Allergic rash

Visiting department

dermatology

Common locations

whole body

Common symptoms

Abdominal pain, crying, and no vomiting

Type: Disease

Attribution system: Dermatology

The main symptoms are: abdominal pain, uneasy crying, no vomiting and diarrhea, a flaky rash around the body, rising above the skin, and redness. Facial torso rash. With fever, or a spot-like dense rash throughout the body, and itching all over the body.

Allergic rash is also called

There are two necessary factors for the development of allergic rash: allergic constitution and contact with drugs, both of which are indispensable. Allergies are genetically determined. People with genetic allergies account for about 1/3 or more of the population. These people are prone to allergic diseases such as allergic rhinitis, bronchial asthma, urticaria, eczema, etc. Another factor is Exposure to sensitizing drugs. Not all medicines can cause allergic reactions. Drugs that can cause an allergic reaction are called sensitizers. Therefore, allergic rashes only occur in people with allergies and must be caused by medication.

The clinical manifestations of allergic rash are various and can belong to any type of allergic reaction, and in many cases, it is a combination of polymorphic allergic reactions.

Dermatological treatment principles and drugs

From the perspective of treatment, skin diseases can be summarized into four categories, and their treatment principles are:

Allergic skin diseases: such as drug allergic dermatitis, contact dermatitis, urticaria, etc. This kind of skin diseases ~ like internal anti-allergic drugs, topical drugs are mainly symptomatic treatment.

Infectious skin diseases: such as pustular sores and scabies caused by staphylococci; zoster, simple scars, and warts caused by viruses; ringworm, athlete's foot, ringworm, and ringworm caused by fungi; ; Dermatitis caused by parasites, rice field dermatitis, etc .; In addition to external use of anti-infective drugs for this type of skin disease, anti-infective drugs should also be used internally in severe cases.

Tumor-like skin diseases: Malignant tumors such as squamous cell carcinoma and basal cell carcinoma are generally treated by surgical resection, radiation therapy, or combined chemotherapy, and local drug treatment is generally difficult to work. Benign tumors may also be considered for surgical resection, but smaller patients may not be treated.

Unexplained skin diseases: There are many such skin diseases, including neurodermatitis, psoriasis, vitiligo, alopecia areata, etc. The external medicine is mainly symptomatic, and the internal medicine is based on the situation or symptomatic or targeted. Predisposing medication.

Dermatological treatment drugs can be divided into two kinds of drugs for internal use and external use. In addition to drug treatment, there are physical therapy, radiation therapy, surgery and so on, which can be used in conjunction with. There are many types of drugs for internal use, including oral and injectable drugs. Topical drugs are an important part of the treatment of skin diseases. Although there are many types of skin diseases and their causes are different, as long as the shape of the lesions is similar in the treatment of topical drugs, similar drug types can be used. Therefore, in the treatment of skin diseases, in addition to understanding the pharmacological effects of various topical drugs, the physical effects of various commonly used drug dosage forms must also be mastered.

Allergic rash topical

Generally according to their therapeutic effects can be divided into the following categories:

1. Protective agents These drugs are non-irritating, mild in nature, can protect the skin, reduce friction, prevent external stimuli, and have the effects of absorption, drying and convergence. Commonly used are zinc oxide, talc powder, and starch, which can be used alone or formulated as compound powders, lotions, ointments, and the like.

2. Antipruritic drugs mainly anesthetize the sensory nerve endings, such as 1% phenol (phen01), 1% thymo1, 2% to 5% lidocaine (1idocaine), 1% Dakronine (dyclonine), 5% to 10% benzocaine (benzocaine). Some have a cooling effect on the skin surface, or stimulate the skin to dilate blood vessels, volatilize and dissipate heat and relieve itching, such as 1% mentho1, 1% to 2% borneol1, and 5% to 10% canphor. Wait. Antihistamine drugs such as 3% to 5% promethazine hydrochloride, 3% diphenhydranine hydrochloride (benadryl) can also relieve itching. Various tar preparations such as: coal tar (coaltar), bran oil (pityro1), black soybean tar (black soybean tar), etc. Although they are keratin promoters, they also have antipruritic effect and can be formulated into vinegars, ointments, etc. Use, can also be used in lotions.

3. Antibacterial agents These drugs include disinfection and preservatives, antibiotics, and anti-infective Chinese medicine, which have the effect of killing or inhibiting growth and reproduction of bacteria. Commonly used antibacterial agents in dermatology are: 1: 5000 8000 potassium permanganate, 3% boric acid, 0.02% furacillin, 1: 2000 new Jie Erfen, 0.1% rivano1 (yishaya (Ethacridine) solution or 0.5% levano ointment, 0.5% to 1% neomycin, 2.5% to 10% ammoniated mercury, 0.5% bacitracin , 0.3% ciprofloxacin, mupirocin and other ointments or emulsions. Traditional Chinese medicines such as: Coptis chinensis, Cork, aster, wild chrysanthemum, senecio, holly, horse teeth, etc. can be made into water, tincture, oil, ointment and so on.

4. Antifungal agents refer to drugs that can kill or inhibit the growth and reproduction of fungi. Commonly used are 3% to 10% salicylic acid, 6% to 12% benzoicacid, and 2.5% to 5%. Iodine, 5% to 10% sulphur, 10% undecylenic acid or zinc decenoate, 1% to 3% gram mycium (c to rim), or 1% bifonazole ), 1% terbinafine, 10% to 30% glacialacetic acid, etc., can be formulated into esters, ointments or creams according to the different properties of the drug. The traditional Chinese medicine 20% soil mold skin and 10% sheep's hoof root also have fungicidal effects. They can be soaked in vinegar or used as an ester or ointment.

5. Keratin promoters The appropriate concentration of these drugs can promote dermal vasoconstriction, reduce inflammation exudation and infiltration, reduce epidermal edema, slow the proliferation and growth cycle of keratinocytes, and restore the epidermal cuticle to normal. However, if used improperly and at too high a concentration, it can cause irritation and aggravate the inflammatory response. Studies have shown that keratinogenic agents may act during the DNA synthesis phase of the cell cycle, prevent DNA synthesis, inhibit mitosis in proliferating cells, and restore the normal growth cycle. The keratin enhancer with strong effect has various tar preparations such as coal tar, pine tar, bran oil, black soybean oil, etc., and 0.1% to 1% anthraline. ), 1: 8000 20000 mustard gas (dichloroaethylsulfide), etc., weaker effects are 10% ichthyo1, 10% sulfur, 5% resorcino1, 2% salicylic acid , 5% Bailuo mercury. Keratin promoters are usually formulated as ointments or esters. It should be noted that if the concentration of the strong keratinizing agent is not properly controlled or the rubbing is applied too frequently, it can cause irritating dermatitis.

6, keratolytic agent can soften the horny, and promote the dissociation of the cuticle of the skin. Commonly used: 5% salicylic acid, 10% rasoxine, 5% 10% lactic acid, 10% sulfur, 0.025% 0.1% tretinoin, 20% urea, can be formulated as ointment, cream Or tincture.

7. The astringent can shrink the capillaries, reduce the lumen, shrink the interstitial space, precipitate the protein in the tissue fluid, reduce the inflammatory serous exudation, and thus have anti-inflammatory, reduce exudate, and promote epithelial recovery. Commonly used are 0.5% to 1% lead acetate (1ead acetate), 5% alum, 0.1% to 0.2% zinc sulfate, 0.5% copper sulfate and the like. 5% formaldehyde (formaldehyde) can inhibit sweat secretion and can be used to treat underarm odor, but attention should be paid to its skin irritation.

8. The corrosive agent has a corrosive effect. Most of them are strong acids and alkalis, which can be used to remove granulation tissue and vegetation, such as 50% trichloroacetic acid, pure phenolic acid, silver nitrate rods, etc.

9. The depigmenting agent can reduce or disappear the skin pigmentation, and its effect can be to inhibit the melanin biosynthesis, bleach, or accelerate the epidermal renewal so as to make the pigment loss. Commonly used are 3% hydroquinone, 20% monophenyl ether hydroquinone, 5% aminomercuric chloride (Halogenol), 20% salicylic acid, 30% razoxin and so on.

10. Sunscreens have the effect of shielding, absorbing and returning light, reducing the damage to the skin caused by sunlight, especially ultraviolet rays. Commonly used: 5% paraaminobenzoic acid (PABA) propylene glycol solution or alcohol solution, 5% titanium dioxide ointment, 10% zinc oxide ointment, 3% to 5% quinine ointment (quinine ointment) and so on.

11. Corticosteroid preparations For external use, glucocorticosteroids are generally used. It has obvious anti-allergic inflammation, anti-epidermal cell proliferation, immune suppression and local vasoconstriction. The mechanism of its anti-inflammatory effect is unknown, but may be due to:

Decrease the permeability of capillaries, reduce the exudation of colloids, electrolytes and cells, etc., reduce the exudate and cell infiltration in the lesion site, and the edema subsides.

Inhibit connective tissue hyperplasia and promote the resolution of interstitial tissue inflammation.

inhibit the activity of inflammatory factors.

Anti-mitotic effect, only the proliferation of epidermal spinal layer was inhibited.

Topical corticosteroid preparations can be generally divided into three types: strong, medium, and weak according to the strength of the vasoconstriction test. At present, domestic commonly used potent preparations are clobetasol propionate (0.05%), halometasone monohydrate (0.05%), halfluxon (halcinonide) (0.1%), acetic acid Fluocinolone acetonide acetate (0.025% 0.2%); intermediate-effect preparations include betamethasone (0.1%), triamcinolone (acetamide acetate) (0.025% 0.1%), and dextran Dexamethasone (0.025% to 1%), fludrocortisone (0.5% to 2.596); weak formulations include hydrocortisone (0.5% to 0.25%) and prednisolone (0.5%) ~ 1%) and so on.

The efficacy of topical corticosteroid preparations is not only related to the chemical structure of the drug itself and its concentration, but also affected by the following factors:

(1) Base The use of soft paraffin as the base of a corticosteroid preparation can be more effective than a cream. Adding dimethyl sulfoxide to the matrix can increase the penetrating power and thus improve the efficacy.

(2) Encapsulation of external corticosteroids with plastic film at the same time can increase the effectiveness by dozens of times, and the packaging time is preferably about 8 hours.

(3) Adding other drugs to corticosteroid preparations in combination with other drugs can not only improve the curative effect, but also reduce the side effects of the added drugs. Clinically used are:

Retinoic acid plus corticosteroid preparations are used to treat psoriasis, which can reduce the stimulation of retinoids and enhance the curative effect.

Urea plus corticosteroid preparations: commonly used anti-inflammatory acetone urea cream, which has a good effect on various types of dry eczema and lichenified eczema. Experiments with radioisotope labeling method have proved that the addition of urea can increase the skin penetration by about 2 times.

Compound preparations made of azole drugs and corticosteroids can accelerate the control of fungal infectious inflammation and receive good curative effects. Indications for topical corticosteroid treatment: neurodermatitis, chronic eczema, psoriasis, late stage of contact dermatitis, etc.

Contraindications Patients who are allergic to corticosteroids, viral infections, skin tuberculosis, or infectious skin diseases (bacteria, fungi). Side effects can occur with long-term application:

Skin atrophy and capillary dilation.

rosacea-like dermatitis reaction, prone to occur with fluoride cortisol hormone.

Inhibition of adrenal function, but temporary.

Allergic rash treatment effect

In addition to the pharmacological effect of the drug, the physical effect of the dosage form also has an important effect. Treatment of skin diseases should be based on different etiology and damage characteristics, the appropriate dosage form can be selected to achieve the desired effect, improper choice of dosage form, the drug can not only play an effective role, and sometimes cause adverse reactions. There are several dosage forms of commonly used drugs for skin diseases:

1. The powder is composed of non-irritating mineral or plant powder, such as zinc oxide, calamine, talc, etc., and the latter such as starch. Commonly used basic prescriptions are zinc oxide talc powder (equivalent amounts), zinc oxide starch (equivalent amounts of zinc oxide, starch, talc powder, etc.), etc. Various types of antipruritic, cooling, and astringent can be added to such basic prescriptions due to treatment needs , Antibacterial and other drugs, such as: 0.5% menthol, 1% camphor, 5% to 10% boric acid, 5% sulfur yellow, 5% Coptis and so on.

Each powder of the powder is a multi-faceted volatile, which has the effects of protecting the skin, dissipating heat, contracting capillaries, reducing inflammation, and absorbing sweat and sebum. The finer the particles, the drier, the wider the heat dissipation area, the stronger the absorption, and the better the effect. Powders are generally used for acute or subacute allergic dermatitis with rashes, sweating, and flushing but no exudate. Skin diseases with exudate and purulent discharge should not be used in powders.

2. The lotion is also called water powder, which is added with an appropriate amount of insoluble powder. Shake before use to make it suspend, then apply on the skin. A commonly used lotion is calamine lotion, which has a formula of 15 g of calamine, 5 g of zinc oxide, 5 ml of glycerol, and water to 100 ml. The lotion has a cooling and cooling effect due to the evaporation of water. After drying, it forms a powdery thin layer on the skin and functions as a powder. The glycerin contained in it can moisturize the skin and adhere to the powder. Lotions can be added for antipruritic, anti-inflammatory, astringent and mild keratin-promoting drugs such as 1% phenol, equal amount of mint water, 5% to 10% fishstone fat, 10% sulfur, 2% to 3% rasozine due to the need of treatment , 5% alum, etc. The lotion is suitable for acute dermatitis and the powder has the same indications, and it is more convenient to use than the powder. Adding an appropriate amount of antipruritic agent can be used for urticaria, papular urticaria and some pruritic skin diseases. The lotion is not suitable for skin diseases with erosion, exudate, crusting, purulent discharge or dry, chapped skin. It should not be used on hair.

3. Wet compresses are commonly used as wet compress solutions with slightly acidic, astringent and bactericidal aqueous solutions, such as 3% boric acid, 1: 8000 potassium permanganate, 0.2% to 1% lead acetate, 1: 5000 furacicillin, 1 : 1000 Lifano, 0.5% Lezosin, etc. The method of wet compressing is to soak 4 ~ 6 layers of disinfecting gauze and soak it in the medicine solution, then wring it dry to a degree without dripping, and apply it on the skin lesion. Pay attention to keep the gauze close to the skin, cover with dry gauze, fix with a bandage, and change it 3 to 4 times a day. The changed dressing can be reused after boiling and drying. Wet compresses the heat through the liquid's evaporation and cleaning effect, the disinfection and astringent effect of the medicinal solution, and the absorption and protection of gauze to isolate it from external stimuli. Therefore, it has the effect of local cleansing, temperature reduction, vasoconstriction, inflammation subsidence, exudate reduction, itching Sense of reducing the effect. Wet application is suitable for acute allergic skin diseases such as eczema and contact dermatitis with erosion and exudate. Extraordinary exudate, available astringent solution such as 1% lead acetate solution, purulent secretions, anti-infective drugs such as 0.1% rifano solution and so on. The temperature of the wet dressing solution is preferably room temperature or slightly lower than room temperature in summer, and a little warmer in winter. The wet surface should not be too large, generally not more than l / 3 of the body surface to avoid cold, especially for the elderly and children.

4. Ointment is a cream made by adding oils as a base and adding therapeutic drugs. The commonly used substrates are vaseline, lanolin, dolphins, and vegetable oil. Beeswax must be added to vegetable oil to adjust its hardness. The ointment can enhance the hydration of the stratum corneum and facilitate the penetration of the drug. Therefore, the drug has a better permeability in the ointment, and its effect is longer. Among them, the pulse lipid has good spreadability and penetrability, and it is easy for the drug to penetrate into the skin, but its oxidative rancidity is its disadvantage. Lanolin has better penetrability, second only to dolphins, but poor spreadability. Vegetable oil and petroleum jelly have poor penetrability, but petroleum jelly is stable in nature, difficult to change with drugs, and cheap and easily available. Commonly used lanolin and petroleum jelly are made into a mixed matrix (the ratio is 1: 9) for clinical use. Ointments are generally suitable for dry, hypertrophic, infiltrating lesions of chronic skin diseases such as neurodermatitis, psoriasis, chronic eczema, and the like. In addition, it is also used for skin diseases with deep inflammation such as pimple. The ointment still has the effect of softening the shells and scales and making them easy to remove, so it can be used for various scales and skins with thick shells in a short period of time. Ointments can also promote granulation growth and epithelial repair, so they are often used to treat chronic ulcers. Use various ointments according to the needs of treatment, such as benzoic acid co.ointment (6g salicylic acid, 12g benzoic acid, plus petroleum jelly to 100g) for treating ringworm, 10% fishstone fat ointment for treating diarrhea, and pus For scars, use erythromycin, neomycin, or mupirocin ointment. The ointment forms a film that is not easily permeable to water on the surface of the skin, hinders the evaporation of skin moisture, can increase local heat, and prevents leakage of fluid. Therefore, it is not suitable for skin diseases with high sensitivity and erosion and exudate, such as acute eczema and contact dermatitis.

5. Paste, also known as mud or paste, is composed of adding insoluble powder (about 25% to 50%) to the base of greasy ointment. Commonly used, such as zinc oxide paste (25g zinc oxide, 25g starch, petroleum jelly, lanolin and other amounts to 100g). The properties of the paste can be summarized as a hard, porous, ointment, which is superficial and non-irritating. Ointment has the effect of protecting the affected area, moisturizing the skin, softening the crusts, and removing the scales on the skin surface. It also has the function of heat dissipation of powder, reducing inflammation and absorbing exudate, but its penetration effect is not as good as that of ointment Less effective than powder. The paste has a small effect on the elimination of normal sebum and the evaporation of sweat. It is usually used for subacute skin inflammation, with mild erosion and less exudative skin lesions. The paste has strong adhesion and is not easy to remove after application. It can maintain a long-term effect on the skin. It can be applied thickly around the sinus or fistula to prevent secondary eczema-like dermatitis. The paste should not be used on the hair area.

6. Emulsion is a uniformly mixed creamy paste made by adding water and oil to emulsifier. Due to different emulsifiers, they are divided into water-in-oil type and oil-in-water type. The former is called fat and the latter is called cream (commonly called snowflake cream). The emulsion has the advantages of whiteness and exquisiteness, does not contaminate clothing, is comfortable to use, easy to remove, and has no greasy drawbacks. Emulsions have certain effects such as heat dissipation, cooling, antipruritic and anti-inflammatory. However, the disadvantages of emulsions are that some drugs such as salicylic acid and boric acid can destroy the emulsification and cannot be formulated. They are stored for a long time and are easy to evaporate and lose water and mold. Emulsions are generally suitable for various acute and chronic inflammations. Lipids should be used for dry skin damage in winter, and creams should be used in summer. After use, the water evaporates, and it has a local coolness. Commonly used creams such as fludron acetate acetate, betamethasone cream, and indeed Shusong cream are suitable for allergic skin diseases such as eczema and dermatitis, but not for fungal skin diseases.

7. Tinctures and tinctures are solutions obtained by dissolving or soaking chemicals or crude drugs in alcohols of different concentrations. Formulated by volatile organic drugs is called vinegar. Tinctures and tinctures have the functions of disinfection, sterilization, and antipruriticity. They evaporate quickly, dissolve sebum, absorb certain skin moisture, promote the epidermal cuticle to easily loosen, and expand peripheral blood vessels. Tinctures and tinctures are superficial and not suitable for deep skin diseases. Generally used for superficial skin fungal diseases and spasm skin diseases. The drug has a short but strong effect in alcohol solution, and it is irritating, so it cannot be used for acute or subacute dermatitis with erosion and damage. Dry cleft skin lesions should not be applied. Dermatology commonly used tinctures such as tincture benzoic acid co. (6 to 12 g of benzoic acid, 3 to 6 g of salicylic acid, 75% alcohol added to 100 ml) to treat ringworm and athlete's foot.

8. The oil agent is a preparation based on vegetable oil or liquid paraffin, which has two uses:

Cleaning effect, such as 1% to 5% salicylic acid oil can remove thick scallions.

Therapeutic effects, such as the commonly used 40% zinc oxide oil, have a mild nature, have astringent, easing inflammation, and are suitable for acute or subacute inflammation with a small amount of exudate skin lesions.

9, plaster is made of higher fatty acid lead salt or rubber as a matrix, coated on the surface of the back material, attached to the skin, when the body temperature becomes soft, firmly attached to the skin. Plasters are generally divided into paste plasters (such as zinc oxide adhesive plasters) and medicinal plasters (such as wound dampness analgesics and traditional Chinese medicine plasters). After the plaster is applied, the skin lesions can be sealed to limit the evaporation of water and the release of local heat, so that the stratum corneum stores a certain amount of water and softens, which is conducive to the penetration of drugs and promotes local blood flow. The plaster is suitable for chronic invasive hypertrophic skin diseases, such as localized neurodermatitis. Acute dermatitis is disabled.

10. Tinctures are liquid-type agents, mainly oil solutions, alcohol solutions and emulsions. Such as camphor tincture (20g of camphor dissolved in 100g of peanut oil) has analgesic effect, used for joint pain and sprains, etc. Basic fuchsinliniment (basic fuchsin 0.3g, boric acid 13g, liquefied phenol 5g 10 mg of rasozin, 5 ml of acetone, 10 ml of alcohol, and 100 ml of distilled water. 1) It has antifungal and antipruritic effects and is used for jock itch and tinea pedis. Calamine tincture (calamine, zinc oxide 8g each, peanut oil, lime water 50m1 each) has a protective and astringent effect, and is used for those with acute allergic dermatitis who are dry.

11.The coating agent is made of certain film-forming agents (such as gelatin, zein, polyvinyl alcohol, methyl cellulose, etc.) and plasticizers (such as glycerin) into easily volatile organic solvents (such as ethanol, isopropyl Alcohol, butanol, etc.), quickly evaporate and dry after application, leaving a thin film locally, and continue to adhere to the skin, so that the drug can be gradually released through the skin's hydration to achieve the therapeutic purpose. This dosage form is generally used for chronic non-exudative damage, and can also be used as a protective agent for the prevention of occupational skin diseases.

12. Aerosol is a medicine and a propellant packed into a high-pressure container. When the valve is opened, the medicine is ejected in the form of a mist by the pressure of compressed gas or liquefied gas. It can be used to treat localized neurodermatitis, chronic eczema, prurigo, and to protect wounds and stop bleeding.

Allergic rash precautions

1. Reasonable choice of dosage form

Different dosage forms can have different effects on skin lesions, which can directly affect the treatment effect. For example, in the exudation period of acute eczema, it is advisable to choose a wet dressing. If we use boric acid water or other medicines, a wet dressing can get better results. If you choose an ointment, such as boric acid ointment, although the drug and concentration are the same, it will worsen the inflammation and symptoms. Reasonable selection of dosage forms is one of the important principles for achieving good results in the treatment of skin diseases.

2. Reasonable choice of drugs

Appropriate drugs should be selected according to the nature and stage of the skin disease. For example, during the period of acute inflammation, the skin is highly sensitive. Drugs with mild properties and lower concentrations such as protectants and astringents should be selected. Drugs with strong irritation and high concentrations such as keratolytic agents and strong effects should be avoided. Keratin promoter. Antibacterial drugs should be used for bacterial and fungal skin diseases. The pharmacological effects of topical drugs vary greatly due to different concentrations. For example, salicylic acid ointment can have antipruritic and mild keratin-promoting effects at low concentrations (below 3%), and 5% to 10% have keratin release and exfoliation. , Fungicidal effect, more than 20% have a corrosive effect. Due to the different dosage forms of topical drugs, their properties are also very different. For example, 5% salicylic acid powder (zinc oxygen powder) is not very irritating for athlete's foot, and 5% salicylic acid ointment is ~ irritating. If 5% salicylate is irritating.

3. Pay attention to the delicate skin of reactive females and young people. The skin on the face, neck, vulva and flexor of the extremities is also more delicate. The medication should be gentler. For large areas, the concentration of the drug should be low, and the irritation should be small, especially if it is damaged, more attention should be paid. The same drug works well for one person and may not be effective for another patient, or even allergic. Some drugs are still good at first use, but they can be ineffective for a long time. Therefore, in the course of treatment, we must pay close attention to the individual response of the patient and use medicine flexibly.

4. Grasp the correct method of use. The appropriateness of the medication method can often affect the treatment effect. Wet dressings should be no less than 6 layers of gauze and replaced no less than 3 times a day. Powders and lotions can be used multiple times, and ointments, creams and pastes are suitable once or twice daily. Generally, the paste should not be applied directly to the skin. It should be applied on the gauze and then covered on the skin surface.