What Is an Allergic Cough?

Allergic cough is a type of cough associated with exposure to allergens. The common cause is cough variant asthma, which is a special manifestation of asthma. It is mainly a cough that persists or recurs for more than one month, often with night or early morning attacks Cough, less sputum, worsening after exercise, no clinical manifestations of infection, or ineffective antibiotic treatment after a long period of time, treatment with bronchodilators can relieve cough attacks, often with personal or family allergies. In some patients, cough is also associated with allergies, but the diagnosis of cough variant asthma is not yet possible. The cause may be upper airway cough syndrome, allergic cough or non-asthmatic eosinophils caused by allergic rhinitis. Diseases such as bronchitis.

Basic Information

Visiting department

Department of Respiratory Medicine, Allergy

Multiple groups

Children, allergies

Common causes

Pollen, house dust, dust mites, mold, virus, animal skin, cockroach, feather, food, etc.

Common symptoms

Long-term refractory cough, often induced by inhalation of allergens, intensified at night or in the morning, seasonal, mostly in spring and autumn

Causes of Allergic Cough

Exposure to environmental allergens, such as pollen, house dust, dust mites, molds, viruses, animal skins, cockroaches, feathers, food, etc. often induce allergic cough. Indoor air pollution and harmful gases, such as chemical gases, including the smell of paint, benzene, formaldehyde and other decorative materials, containing various chemical pesticides such as DDV, aroma smoke, soot, soot and mosquito smoke are also common causes. Cold air, climate change, etc. can also cause cough in these patients. With the improvement of modern living standards, new allergens frequently enter people's living areas, people also have more opportunities for business trips, travel, vacations, etc., and the area of activities is constantly expanding, so the range of allergen exposure is also increasing, so allergic cough Prevention and control are often more difficult to prevent. From the perspective of the inconsistencies in the incidence of allergic cough in monozygotic twins, environmental factors may play an important role in the pathogenesis of allergic cough.

Clinical manifestations of allergic cough

The symptoms of allergic cough are mainly long-term refractory coughs, more than 3 weeks, often inhaling irritating odors, indoor air pollution and harmful gases, cold air, allergens such as pollen, indoor dust, dust mites, mold , Virus, animal fur, cockroaches, feathers, food, etc., induced by exercise or upper respiratory tract infection, some patients have no incentive. Intensified at night or early in the morning. Some patients have a certain seasonal attack, mostly in spring and autumn. Vulnerable groups are children and other people with allergies.

Allergic cough test

1. X-ray inspection

A chest radiograph showed normal or increased lung texture but no other organic changes.

2. Check for airway reversible obstruction

Mainly bronchodilator test and peak expiratory flow velocity variation rate detection. When the patient's vital capacity falls below 70% of the normal expected value in the first second, a bronchodilator test is needed. The peak expiratory flow rate variability test is mainly used in the absence of equipment to perform bronchial challenge or diastolic test inspections. Generally, continuous monitoring is required for at least 2 weeks. When the peak flow rate variability is> 20% for at least 3 days per week, it is determined to be positive.

3. Detection of airway hyperresponsiveness

This is the main method for diagnosing bronchial asthma, including cough allergic asthma. The bronchial provocation test, also known as airway reactivity measurement, is to use different stimuli to trigger abnormal contraction of the bronchus, and then measure the lung function again to determine the pulmonary function index. Changes in the situation, to determine the degree of airway hyperresponsiveness. Choline drugs such as methacholine are often used for testing. A positive bronchial provocation test is indicated when FEV1 decreases by 20% or more. This test is often positive for patients with bronchial asthma or patients with airway hyperresponsiveness. Provocation tests for patients with diseases such as upper airway cough syndrome, allergic cough, or non-asthmatic eosinophilic bronchitis are often negative.

4. Allergen detection

For patients with allergic cough, an allergen test needs to be performed to identify the allergens as early as possible in order to take appropriate preventive or therapeutic measures. There are currently two recognized allergen detection methods:

(1) In vivo tests, that is, skin tests (including intradermal injections, skin scratch tests, skin prick tests, etc.);

(2) In vitro tests, in vitro tests performed by collecting blood, mainly detecting specific lgE in serum for screening of common allergens.

Allergic cough diagnosis

Reference criteria for the diagnosis of cough variant asthma:

Cough is the only or main symptom. It has no typical symptoms of asthma such as wheezing and shortness of breath, and has any of the objective examinations of variable airflow limitation, except for cough caused by other diseases.

Allergic Cough Treatment

Although cough variant asthma is usually not life-threatening, as cough variant asthma can develop into typical asthma, and the disease can seriously affect sleep, work, and study, it should be diagnosed and treated early. Once a cough variant asthma is diagnosed, antibiotics or antivirals should be discontinued and care should be taken to avoid contact with allergens.

Drug treatment

(1) Inhaled glucocorticoids are mainly used for anti-inflammatory treatment. The duration of inhaled glucocorticoids should be at least 3 months to prevent recurrence. Commonly used in clinical practice are hormones and 2 receptor stimulants such as Symbioco and Shulidie.

(2) Tracheal dilators such as inhaled or oral 2 receptor stimulants or / and oral theophylline drugs can temporarily relieve cough symptoms, but it is not recommended to be used alone for a long time.

(3) Anti-allergic drugs such as levocetirizine, loratadine, and mast cell stabilizers such as Nedocromil, sodium cromoglycate can also receive good results, but often need to be continuously applied for more than 2 weeks. Patients who have recurrent episodes after discontinuation of the drug should promptly identify allergens, take effective preventive measures, and give allergen vaccine treatment if necessary.

(4) Montelukast, a leukotriene receptor antagonist, which is known as a "dual-channel" drug for the treatment of asthma with hormones.

2. Chinese medicine treatment

Traditional Chinese medicine believes that it is mainly related to "wind" and "phlegm". In the acute phase, Chinese medicine that expels wind and phlegm is used to relieve wind, clear the lungs, reduce phlegm, and relieve cough. Good effect.

Allergic cough prognosis

The prognosis of allergic cough is related to the age of onset, the severity of the disease, the duration of the disease, and the treatment method. Early detection and symptomatic treatment have a better prognosis.

Allergic cough prevention

1. Rest and keep warm

Children should reduce activity, increase rest time, head and chest slightly raised while in bed, so that breathing is unobstructed. The indoor air is fresh, maintaining proper temperature and humidity, and avoiding convection wind. Avoid emotional excitement.

2. Pay attention to allergic cough taboo diet

Avoid cold and cold foods, spicy spicy and fishy foods; take care of fatty and sweet tastes, such as fatty meat, sweet drinks, sweets, etc .; avoid foods that can cause allergic symptoms. Serve seafood such as shrimp and crab with caution. Patients with allergic rhinitis or allergies should avoid taking it.

3. Keep the room ventilated, dry and clean

Change the pillowcase and quilt frequently, remove dust mites and their metabolites, and place them in the sun for a long time.