Allergy laboratory

Skin prick test

Summary

Science

Clinical

Clinical

Allergen exposure is a quick and accurate way of determining the allergen responsible for the hypersensitivity. It can be used for hundreds of suspected allergens. If an allergy consultant suspects that a patient may be allergic to a substance because they presented with symptoms after a unique exposure, for instance a meal in a restaurant, then they may try a skin prick test to investigate. A range of allergens may be used that reflect the suspected exposure, such as the ingredients of a dish served in a restaurant. In addition a set of common allergens, such as grass, cat dander, dust mite can be used to check for sensitivity. Whilst the test is extremely useful it is essential that the clinician considers the drawbacks with the test and may consider another approach. One such drawback arises if the individual is already on antihistamine drugs, in this case the test may not work at all. Alternatively if the patient has a predisposition to react severely to an allergen, such as with peanut allergy, then even this slight exposure may lead to a severe, life-threatening allergic reaction called anaphylaxis.

Once a specific allergy is diagnosed, a range of measures can be employed to reduce the number and severity of future reactions. Individuals with sensitivities that provoke asthma can be given inhalers that can prevent and reduce symptoms during summer months. Allergy drugs called anti-histamines can also be given to reduce symptoms. In cases, where the allergy can lead to severe allergic reactions (anaphylaxis), people may be equipped with “epipens” that give an injection of adrenalin to ease symptoms. Ultimately the test provides the patient information about what substances to avoid.
Accurate diagnosis can dramatically improve the quality of someone’s life by making him or her aware of substances they should avoid, and giving them the necessary strategies to cope with a reaction if they are exposed.

• Science