Hypersensitivity to
para-phenylenediamine (
PPD) and related compounds induced by temporary
black henna tattoos has become a serious health problem worldwide. Different patterns of sensitization with various clinical aspects are described in literature due to
PPD associated to henna
tattoo and these manifestations are likely correlated with the immunological and dermatological pathomechanisms involved. Henna is the Persian name of the plant Lawsonia inermis, Fam. Lythraceae. It is a woody shrub that grow in regions of North Africa, South Asia, India and Sri Lanka. Nowadays it is rather frequent to see temporary "
tattoos" performed with henna. To make
tattoos darker and long-lasting
PPD has been associated to henna in
tattoo drawings mixtures, so obtaining "
black henna". In these years there has been a rise of contact sensitization to
PPD and in medical literature an increased number of cases have been reported on temporary henna
tattoo application. Here we review the various clinical patterns related to
PPD and henna
tattoo, to investigate the possible link between clinic-morphological pictures and the immunological response to
PPD and henna. The literature underlines that different clinical manifestations are related to
black henna containing
PPD, and its derivative products may cause delayed-type as well as immediate-type reactions. Further studies are needed to investigate the relationship between clinical and morphological aspects of
PPD contact dermatitis and the T cell subsets predominance.