Frictional asymptomatic darkening of the extensor surfaces.

Frictional asymptomatic darkening of the extensor surfaces (FADES), also known as hyperkeratosis of the elbows and knees, is commonly seen by dermatologists but has never been well characterized. Patients present with uniform, asymptomatic, brown darkening over the extensor surfaces of the elbows and knees with minimal scaling. Both frictional stress and family history may play a role in the pathogenesis of this condition. The results of cutaneous biopsy specimens typically reveal hyperkeratosis, acanthosis, and mild papillomatosis with minimal inflammation. Keratolytic agents such as lactic acid and urea cream along with avoiding frictional stress can be effective in the management of this condition. We describe a series of cases of FADES and its etiology and management options.