Allergic diseases in children are quite common nowadays. Their timely diagnosis with the help of allergy tests makes it possible to ease the course of the disease, achieve recovery and prevent the development of severe forms of allergies.
What are allergy tests?
Allergic tests are tests during which a child's sensitivity to allergens is determined. Also, such studies are called allergy diagnostics.
Indications
A child is prescribed allergy tests if he has:
- Allergy to food;
- Atopic dermatitis;
- Bronchial asthma;
- Inflammatory diseases of the respiratory system;
- Hay fever;
- Allergy to drugs.
Contraindications
Skin allergy tests are not performed:
- Under the age of 3;
- During an exacerbation of an allergy (tests can be performed no earlier than 3-4 weeks after the last exacerbation);
- In acute infectious diseases;
- With primary immunodeficiency and exacerbations of autoimmune diseases;
- If the baby has had anaphylactic shock in the past;
- If the child has severe somatic diseases with decompensation;
- After taking antihistamines.
Types and methods of diagnosis
Skin tests are divided into:
- Scarification. They are used to detect reactions to non-infectious (food, household, pollen, fungal, and others) and infectious allergens.
- Prik tests. Most common for detecting respiratory allergies.
- Intradermal. It is most often used to detect a reaction to infectious allergens.
- Dermal. They are carried out using applications (if contact dermatitis is suspected) or by the drip method (with very high sensitization).
Cons compared to a blood test
With a skin test, the child is in contact with allergens, therefore, he can respond to this type of research with an allergic reaction of varying severity, up to anaphylactic shock. That is why skin allergy tests are performed only in medical institutions.
- Allergic skin examinations can only be carried out after 3-5 years. In addition, for this, the child should not have an aggravation. A blood test can be done at any age and even in the presence of an exacerbation.
- Skin tests are more painful, and the examination itself takes longer.
- The method of skin tests can reveal a reaction to 5-20 allergens, while a blood test can assess the sensitization of a child's body to more than 200 allergens.
Training
If the child is taking antihistamines, they are canceled 5-7 days before the skin tests. There are no other nuances of performing these analyzes, for example, the conditions to come for an examination on an empty stomach.
How is the analysis done?
The test will depend on its type:
- If an application test is carried out, the tissue with the allergen applied to it is applied to the child's skin for 2 days. During this period, the fabric should not be wetted.
- During the scarification test, the child's skin is treated with drops of various allergens, then shallow scratches are made through them.
- The same technique for the behavior of prick tests, only instead of scratches, mini-injections are performed, the depth of which is up to 1 millimeter.
- For intradermal tests, allergens are injected into the baby's skin.
Results
Scarification and prick tests are assessed 15-20 minutes after the application of allergens to the skin. The presence of a reaction to an allergen is noted by swelling and redness. Further, the assessment of the local reaction is carried out after another 24 hours and after 48 hours. A test is considered positive, during which a papule of more than 2 millimeters appeared.
The assessment of the application skin test is carried out after two days for the presence of itching, redness and irritation in the place where the bandage was applied.
