A healthy 30-year-old woman obtained a henna "tattoo" from a street vendor on a California beach. Ten days later she noted pruritus followed by multiple small papules overlying the pattern encircling her left arm. Several days later, the design appeared erythematous and raised, sparing the unpainted areas (Figure 1). Treatment with topical diflorasone diacetate resulted in gradual improvement with resolution in several weeks. The patient denied prior exposure to henna. She chose not to have a skin biopsy and patch testing to henna. However, the time course and clinical morphology of the dermatitis were typical of a type IV hypersensitivity reaction to henna.
Lyon MJ, Shaw JC, Linder JL. Allergic Contact Dermatitis Reaction to Henna. Arch Dermatol. 2000;136(1):124-125. doi: