The Danger of Disappearing Allergen Skin Test Substances

Allergic diseases affect approximately one-quarter to one-half of the average population under 50 years of age in Central Europe. Due to the high proportion of affected individuals, allergy testing needs to be performed on a large scale, with high sensitivity and specificity at a low cost. Skin tests are the most important diagnostic measure fulfilling these requirements: they can be performed immediately and, quite in contrast to laboratory tests, the results of skin prick tests for the diagnosis of immediate allergy (IgE-mediated: Type I) can be assessed, and discussed with the patients 15–20 minutes later. Patients do not need to be called in for a second appointment to discuss the results of serum-based determination of specific IgE. Recently, we demonstrated that the sensitivity of skin prick tests is superior to the measurement of allergen-specific IgE, even for modern molecular allergens. In T cell mediated allergy of the delayed type (contact dermatitis: Type IV), patch tests read after 48–72 hours are the only available diagnostic measure.