Many of you may have heard doctors talk about “allergic diseases” and know that chronic runny nose, chronic cough, chronic rash, or chronic diarrhea are among the symptoms of allergic diseases. However, allergic diseases actually have many details that we may not yet know. If you wonder what allergic diseases are, why they occur, and why their symptoms vary in many forms, today we have the answers…
What are allergic diseases?
Allergic diseases are conditions in which the body reacts abnormally to allergens, causing chronic inflammation of the mucous membranes of various organs in the body, such as the skin, nasal mucosa, conjunctiva, respiratory tract mucosa, or gastrointestinal mucosa, etc. Patients with allergic diseases will have symptoms in the organs where inflammation occurs due to stimulation by different allergens.
What symptoms correspond to which allergic diseases?
- Skin symptoms: Atopic dermatitis. Patients will have chronic itchy rashes on the face, folds of arms and legs, or trunk, etc.
- Nasal mucosa symptoms: Allergic rhinitis or hay fever. Patients will have chronic runny nose along with sneezing, itching, or nasal congestion.
- Conjunctiva symptoms: Allergic conjunctivitis. Patients will have chronic itching or eye irritation, burning sensation, or frequent tearing.
- Respiratory tract mucosa symptoms: Asthma. Patients will have cough, difficulty breathing, chest tightness, or wheezing sounds when breathing.
- Gastrointestinal mucosa symptoms: Food allergy. Patients will have chronic diarrhea, vomiting, weight loss, along with chronic rash and anemia.
Types of allergens
There are 2 types of allergens:
- Airborne allergens such as dust mites, cockroaches, dog hair, cat hair, grass pollen, or mold. Dust mites are the most common airborne allergen found, especially in bedding, bed sheets, pillowcases, comforters, or carpets in the bedroom. Dust mites thrive well in suitable temperature and humidity conditions.
- Food allergens such as cow’s milk, soy milk, peanuts, eggs, seafood, or wheat flour.
Magnified image showing dust mites
Factors causing allergic diseases
Currently, no definite cause of allergic diseases has been found, but factors related to the occurrence of these diseases include:
1. Genetic factors It has been found that children with a father or mother who has allergic diseases have a 20-40% chance of developing allergies. If both parents have allergic diseases, the child has a 50-80% chance of developing allergies. However, about 15% of children develop allergies without a family history of allergic diseases in their parents.
2. Environmental factors
- Changes in urban living Moving to live in cities, living in closed houses, using air conditioning, carpeting, having furniture and home decorations that accumulate dust.
- Air pollution caused by vehicle exhaust emissions and pollution from various industrial factories.
- Cigarette smoke contains many toxic substances, including carcinogens and irritants to the respiratory mucosa. Children with parents who smoke at home, especially if the mother smokes, have twice the risk of developing asthma compared to normal children.
3. Nutritional factors
- Breast milk Children who are exclusively breastfed have a lower chance of developing asthma and other allergic diseases than children who are fed with formula.
- Food Foods that have undergone various processes such as freezing, adding color, flavor, or consuming more starch and fat than plants, vegetables, and fruits.
How to know… which allergens you are allergic to
When symptoms suggest allergies, we can test with tools and test solutions to find out which allergens cause the allergy, so treatment can be given and precautions taken to avoid contact or ingestion of allergens. There are 2 testing methods:
- Skin testing Skin testing provides more accurate results than blood tests, but children often fear or do not cooperate during the test, which may cause inaccurate results. In such cases, blood testing may be necessary.
- Blood testing Blood testing is suitable for children who do not cooperate with skin testing and is also useful in the following cases:
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- Children or patients with severe atopic dermatitis who cannot stop taking antihistamines, as patients generally need to stop antihistamines for at least 1 week before skin testing.
- Children or patients with atopic dermatitis who do not have enough normal skin for skin testing.
Skin testing equipment
- Skin test solutions
(Cleaning the skin area to be tested)
- Tray for skin test solutions
- Skin testing device made of plastic with 8 sharp tips, convenient because it can test 8 allergens at once
How to perform skin testing
- Dip the plastic device with sharp tips into the tray containing allergen solutions, which are labeled according to their positions in the tray.
- Clean the skin area to be tested, such as both forearms or the back.
- Place the device dipped in allergen solutions on the cleaned skin area and press firmly but gently.
- The patient will feel slight pain at the test site but there will be no bleeding because the device is made of plastic.
- Wait about 2 minutes for the solution to penetrate the skin, then blot the excess solution with paper. During this time, the patient should remain still to prevent mixing of solutions at different test sites.
- Wait 10-15 minutes to read the results. During this time, the patient can perform normal activities but should avoid scratching the test sites. After the time is up, the doctor will read the results, diagnose, and proceed with treatment.
- If the patient reacts to the test solution, swelling, redness, and itching will occur at the site of the allergen, indicating which allergen the patient is allergic to. These symptoms will subside within about 24 hours without scarring. If symptoms are severe, antihistamines may be taken.
How to avoid or treat allergic diseases
- Avoid contact, inhalation, or ingestion of allergens. If the allergen type is unknown, consult a doctor for allergy testing.
- Use medications as prescribed by the doctor, eat a balanced diet with all 5 food groups, get enough rest, and exercise regularly.
Most allergic diseases cannot be completely cured and may frequently recur if exposed to allergens. However, with proper management, patients can live and study normally.
