Detecting the allergens which are the causative factors for allergic diseases is extremely important for the appropriate management of allergy patients. An allergen can give the least is itchy rash and the last/most is anaphylaxis (fatal reaction/death) to an allergic patient and between these, it can give a poor quality of life with various symptoms. All the problems occur as a result of an interaction between the allergens in the environment and the patient’s immune system resulting in the release of histamine and other pro-inflammatory mediators.
An inaccurate diagnosis simply on suspicion/prediction may often be the cause of unnecessary avoidance of your favourite food lifelong which may cause malnutrition/growth retardation.
According to World Allergy Organisation (WAO), though 30-40% of world population suffer with allergy, people sometimes be unware that their lives can be improved and keep them safe from sudden death due to anaphylaxis.
While someone comes in contact to an allergen their own immune system react to it and produce allergen specific IgE antibodies and allergic science now can detect them very well.
Some people have inherited tendency to produce these antibodies classified them as atopic. The atopic people are prone to eczema, food allergy, asthma and hay fever etc. Atopic children may develop these manifestations one after another as a sequence and persist over a period of time this is known as atopic march. However, they often remit spontaneously while they grown up.
Medical professionals can decide after an allergy focus interview of the patient, what are the allergens should be tested. For instance, if a patient suffers with allergic rhinitis (hay fever) or asthma, doctor may advice for the following allergens; pollen from relevant grasses, weeds, trees, house dust mite, cat, dog, horse, rabbit dander, if history suggests, mould, some food allergen and stinging insects venom.
Two tests are commonly used to detect allergen specific IgE antibodies, the Skin Prick Test and the Specific IgE Blood Test (previously known as RAST: Radioallergosorbent Test).
The important thing is that detection of the antibody does not mean that someone is allergic, it means allergen specific IgE is present (i,e. the immune system has become sensitised as like as loaded gun but not fired) and the negative result did not also mean that the individual is not allergic. Negative test may point toward a different explanation or other form of allergy. This is why interpretation of allergy tests need a medical professional who have at least a training in allergy.
However, for a confirmation of diagnosis of allergy, in addition to the allergy tests, an allergy focus interview is important. In some cases to reach a diagnosis an allergist may consider a provocation challenge (gold standard amongst allergy tests) test to avoid the confusion. However, this should be done in hospital environment under specialist supervision.