Frictional dermal melanosis (lifa disease) over bony prominences.

Seventy-one patients (70 females and one male) were studied. Their ages at presentation ranged from 16-43 years with a mean of 24.4 years. The duration of disease varied from three months to ten years with a median of 2.7 years. All patients were slim and had recorded using a washing agent (Lifa) during bathing with vigorous friction. Family history of the same disease was present in 11 (15.5%) patients. The pigmentation was brown-black with a rippled pattern and showed no contrast under Wood's light. The areas commonly affected were clavicles (71.8%), shins (36.6%), upper back (32.4%), Adam's apple (31%), lateral aspects of the arms (31%) and other areas. The histopathology of biopsies from 24 patients showed marked dermal melanosis. Amyloid deposits in the papillary dermis were present in one patient. This clinical and histopathological picture suggests that this common condition is related to frictional melanosis.