2022 Volume 46 Issue 4 Pages 379-384
Cosmetics can cause allergic contact dermatitis, irritant contact dermatitis, contact urticaria, depigmentation, and other skin disorders. The skin testing methods for allergic contact dermatitis and allergic contact urticaria are described in this paper. A 48-h closed patch test, open test, or repeated open application test (ROAT) is used to diagnose allergic contact dermatitis, which is a delayed allergy. A photopatch test is required to test photoallergic contact dermatitis. Rinse-off cosmetic products should be diluted with 1% aqueous solution and applied for 48-h closed patch test, while powder products should be mixed with approximately 30% petrolatum and applied. Hair coloring agents and permanent wave agents with irritant properties should not be subjected to closed patch test but instead undergo an open test. It is also useful to perform a ROAT to diagnose allergic contact dermatitis. On the other hand, a prick test should be performed to diagnose contact urticaria, which is an immediate allergy.
