FADES

The patient is a 17 yo boy with a 10 year history of asymptomatic hyperkeratosis of both elbows.  His knees are normal.  He has no personal history of atopy and both he and his mother deny that he rubs or scratches the area.  He's embarrassed by this and avoids sports as a result.  He is moderately obese and does not exercise or do sports.

O/E:  Symmetrical hyperkeratosis of both elbows.  Knees perfectly normal as is the remainder of his cutaneous exam.  He is moderately overweight.

Clinical Images:

Diagnosis: Asymptomatic Frictional Hyperkeratosis of the Elbows

Comment:  I suppose we all see this entity on frictional sites, but rarely name it.  The patient denies rubbing or scratching the area but was observed to lean on his elbows.  A similar problem has been reported (see reference  1. below).  I recommended starting with 5% Keralyt gel twice daily and may add tretinoic acid.  I propose that this type of hyperkeratosis can follow pressure on bony prominences, such as is seen on the foreheads of devout Muslims who pray 5 times a day (2).  Prayer marks in Muslims appear to be more common in diabetics (3).  The patient described in this VGRD  post could well have the metabolic syndrome.  I wonder if this might be important. I'd appreciate your  thoughts. 

Reference:

1. Frictional asymptomatic darkening of the extensor surfaces.

Krishnamurthy S, Sigdel S, Brodell RT. Cutis. 2005 Jun;75(6):349-55.

Abstract: 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.

Comment in: Frictional asymptomatic darkening of the extensor surfaces. [Cutis. 2007]

2. Prayer marks. Abanmi AA et. al. Int J Dermatol. 2002 Jul;41(7):411-4.

Prayer marks (PMs) are asymptomatic, chronic skin changes that consist mainly of thickening, lichenification, and hyperpigmentation, and develop over a long period of time as a consequence of repeated, extended pressure on bony prominences during prayer. PubMed.

3. Prayer Marks in Immigrants from Bangladesh with Diabetes Who Live in Greece.  Papadakis G, et. al. J Immigr Minor Health. 2016 Feb;18(1):274-6. PubMed.