Contact dermatitis is a disorder caused by contact with an external substance that triggers an allergic response. The history taken by the allergy/immunology specialist is important for the diagnosis and management of the disease. Common triggers include: sunscreen; Fragrant soaps; Shaving lotions; Rubber; Certain deodorants and perfumes; Bleach; Hand sanitizers; home fragrance diffusers, preservatives and emulsifiers, hair dye, shampoos.
A special test called patch test is indicated in any patient with acute or chronic dermatitis. Patients are typically asked to wear the patch for 48 hours, keeping it dry for that period. The allergist will then ask to return twice to check on the reaction. The patch test conducted by an allergist will determine what caused the reaction so that the allergen or irritant can be avoided in the future. The patient will receive a list of what they are allergic and also a list of products that they can use.