'Black henna' tattoos: an occult source of natural rubber latex allergy?

Temporary 'black henna' tattoos are an increasingly popular body decoration with a growing incidence of associated adverse events. We report the case of a 14 year old girl presenting with an acute allergic contact dermatitis to hair dyes. Some years previously she had a 'black henna' tattoo with prior application of a tacky transfer to the skin to outline the design followed some days later by an acute localised blistering reaction. Patch testing to an extended British Contact Dermatitis Society standard series showed relevant positive reactions to paraphenlyenediamine (PPD) and thiuram mix, as well as to several of the azo disperse dyes. We went on to perform prick testing to natural rubber latex (NRL), showing a positive reaction to the commercial HEP 100 concentration. We propose that through the initial acute reaction caused by PPD in the 'black henna' our patient was not only sensitized to PPD, but also to thiuram and natural rubber latex which may have been present in the tacky transfer applied prior to 'tattooing.' We would add that temporary 'black henna' tattoos may have more important consequences than previously thought on patients' future health by sensitization to NRL.