Common causes of contact eczema are the metals nickel and cobalt, chromate ions, hair dyes and substances used in permed hair, aromas and fragrances in cosmetic products. Epicutaneos testing either confirms or rules out type 4 allergies (delayed type). Here, small amounts of precisely defined substances suspected of triggering the eczema are applied to the back of the patient. Depending on the profession of the patient, targeted serial testing specific to the patient’s profession or with specific substances may be carried out.
Prick testing is performed in food allergies and inhalation allergies (pollen, house dust, moulds, animal hair). A detailed patient interview by the physician is the foundation in the diagnosis of an allergy and a key element in the search for its underlying cause. In prick testing small amounts of purified allergens are introduced into the upper layers of the skin of the lower arm. The reaction can be assessed after a short wait of just 20 minutes.
Prick to prick testing
In prick to prick testing substances (usually raw food) are applied to the skin for 20 minutes. After this contact time, lighter cases will demonstrate reddening and minor itching, while more severe cases evidence local welts with itching.
In intracutaneous testing certain allergens are injected into the skin with a thin needle. Testing may be for pollen, food, moulds, animal hair, and house dust among others.
In provocation testing diluted allergen solution is directly applied to the mucous membranes of the nose, bronchi or the conjunctiva of the eye. After about 5 minutes any allergic reaction of the mucous membrane will appear as swelling, secretion, tears, or increased resistance to breathing. In general, provocation testing is performed only if there is a discrepancy between the results obtained from the interview with the patient, skin testing and the blood tests. Individual provocation testing mandates an inpatient setting because its course may become extremely dramatic.
We proudly offer a specialized allergology clinic directed by Prof. Bernhard Przybilla, MD, PhD, former Chair, Department of Allergology, LMU University Munich in Germany.