<unk>  is a form of contact dermatitis, beginning with pruritus, erythema, and pigmentation that gradually spreads which, after reaching a certain extent, becomes stationary. The pathogenesis of<unk>  is believed to be sun exposure following the use of some perfumes or creams (a photocontact dermatitis).<unk>  is named after the dermatologist Gustav<unk> , who first described the condition in 1917.
Riehl melanosis
Erythromelanosis follicularis faciei et colli
Blue nevus
Spitz nevus
Smoker's melanosis
Terry's nails
Becker's nevus
Phakomatosis pigmentokeratotica