Contact urticaria from curcumin.

Turmeric, a spice derived from the rhizome of the plant Curcuma longa, contains the chemical curcumin, which is responsible for turmeric's taste, color, and biologic properties. Curcumin is used as a spice in foods, as a treatment in traditional medicine, as a dye for fur, and as a component in nutritional supplements. A few cases of allergic contact dermatitis from curcumin have been reported. We report two cases of contact urticaria from curcumin. These cases are mediated by two different mechanisms of contact urticaria: nonimmunologic and immunologic (immunoglobulin-E mediated).