skin patch testing
Last reviewed 01/2018
This is used in all cases of suspected contact dermatitis to investigate allergic contact dermatitis. A battery of some 25-40 allergens are put into individual aluminium chambers and placed on the back with hypo-allergenic adhesive. They are marked and read after 48 hours. Interpretation is difficult and should be performed by an experienced dermatologist.
Some of the more common allergens included in the test are potassium dichromate, neomycin sulphate, thiuram, cobalt chloride, benzocaine, formaldehyde, quinolone, rubber, wool alcohols, balsam of Peru, epoxy resin, nickel sulphate, mercaptobenzothiazole and ethylenediaminedihydrochloride.
Preparation is important for results to be accurate. Materials containing suspected allergens should be avoided and any lesion cleared using appropriate topical therapy.