LAUSR

Use of complementary and alternative medicine has increased in industrialized countries. Nigella sativa oil (NSO), used as an herbal medicine for thousands of years, has drawn interest for its immunoregulatory, antimicrobial, cardiovascular, and antitumoral properties. Although patients expect alternative medicine to be safe, allergic contact dermatitis (ACD) and bullous dermatitis with NSO have been reported. The hypothesis that thymoquinone (TQ), its major component, is the causative substance of allergic reaction to NSO was proposed, but thymoquinone is not yet available in France for patch tests. Only NSO patch tests can be performed. In one recent case report we reported that due to a close chemical structure between tert-butylhydroquinone (TBHQ) and TQ, positive patch tests with TBHQ, TQ, and NSO could be observed, suggesting that TBHQ could be a marker for sensitivity to TQ and so to NSO. To confirm this hypothesis, we report the results obtained in five consecutive patients with ACD to NSO also having been tested with TBHQ.