Allergic contact dermatitis to an expired moisturiser.

A 64-year-old man developed an allergic contact dermatitis while using an expired sorbolene cream. Patch tests to the product ingredients were all negative. Repeated open application test to the expired product produced a strong reaction while an identical-brand non-expired product did not elicit a reaction, suggesting the presence of an unidentified degradation product or compound, acting as an allergen in the expired product. This case is intriguing in that it contrasts the ubiquitous use of over-the-counter topical agents with the exceedingly low incidence of contact dermatitis to expired topical products.