Temporary henna tattooing has been very popular during recent years. Henna (Lawsonia inermis) is a plant from the Lythraceae family. For henna tattooing, henna dye is used. It is a dark green powder, made from the leaves of the plant, used for hair dyeing and body tattooing. Very often, para-phenylenediamine (PPD) is added to henna dye to make color blacker and to speed up dyeing. PPD may be a very potent contact sensitizer. We report a 9-year-old boy with allergic contact dermatitis due to temporary henna tattooing. Patch testing showed a positive reaction to PPD. After the treatment with topical corticosteroid and oral antihistamines, the lesion cleared with discrete residual hypopigmentation.