To determine if a patient has an allergic sensitization to a given substance, effective tests are used to expose the skin to the suspect element. At this point, the Pediatric Allergy Specialist in Starkville MS will observe what happens next. Several methods are available but how do these allergy skin tests work?
Food, pollen, mites, medicines, animal hair, wasp or bee venom: numerous agents are likely to trigger an allergy in any given person, which is linked to an abnormal and excessive reaction of the immune system. There are two types of allergy processes to consider.
• Immediate allergies involve IgE antibodies (immunoglobulin E) – This mechanism is determined by a “prick” test and its associated intradermal reaction. The reaction is read after 20 minutes.
• Delayed allergy testing mobilizes certain white blood cells (lymphocytes) – This mechanism is evaluated by the patient’s intradermal reaction and associated patch test. Reading occurs between two and four days later.
It should be noted that allergic sensitization does not necessarily mean that the person suffers from an allergy: the test may be positive when no symptoms are observed. Allergic skin tests do not require any specific preparation (the patient should not be fasting, for example). They can be carried out at any age (and from birth, in fact).
These examinations are not of an urgent nature. Moreover, a “prick” test lasts about twenty minutes. The Pediatric Allergy Specialist in Starkville MS will use the patient’s forearm or back for testing. This test examines environmental allergens (animal hair, dust mites, pollens, molds, latex, and so on), foods (marketed or fresh products), and medicines.
A drop of allergen is deposited on the epidermis. Using a tiny tip, the substance is introduced just below the surface of the skin (1 mm) to be brought into contact with the antibodies (IgE) involved in the allergy. The test is considered positive if certain “reactions” occur within twenty minutes.
These reactions consist of redness, tingling, or swelling. These manifestations disappear within one hour (if the patient does not scratch the area). It is possible that slight reactions occur after a few hours (they fade in one or two days), but this is not significant for the evaluation of an immediate allergy.
Visit Children’s Health Center of Columbus Inc. for more details.