Allergic contact dermatitis from gardenia fruit

A 41-year-old man, with severe itchy dermatitis on the left leg, had treated a bruise on the left knee with a topical folk remedy called Sokujikoh, which contains about 16% powdered gardenia fruit. After 4 days, an exacerbation of symptoms appeared, with edema, erythema, and vesicles on the treated area. Patch testing indicated sensitivity to the seeds of gardenia fruit and, to a lesser extent, the pericarp (fruit wall). The allergens could be extracted into ethanol and, less readily, into water.