Friday, April 27, 2018


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. 


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.


  1. Professor Sharquie from Baghdad writes: I think this patient has hyperkeratotic psoriasis of elbows which is a common manifestation of psoriasis especially on elbows and knees .This picture could be also associated and combined with frictional hyperkeratosis and biopsy might prove this diagnosis.
    Frictional hyperkeratosis is very common problem especially on frictional areas like knees,elbows and forehead,also frontal parts of feet are effected by hyperkeratotic patches and plagues as a result of sitting on them during eating and praying.
    Also frictional melanosis over bony prominences (lifa disease)is very common problem and a cause of dermal pigmentation as result of friction with washing agent so called lifa and I have many publications in this regard

  2. It's amazing how the simplest and most common disorders can sometimes lack a name. Frictional hyperkeratosis fits the bill. Most importantly, patients despise it! Assuming that the frictional stimulus remains, I think 40% urea works the best - too bad hardly any prescription plans allow it. Therein lies the rub (sorry, couldn't resist!)

  3. Comment of DR. Ong Cheng Leng, Malaysia: "I can easily recall two gentlemen who have these lesions, they are not my patients but one is my relative by marriage and the other my old friend. Both are well over sixty years old.
    The former has a son who grew up to develop erythrodermic psoriasis requiring biological.
    My friend still suffers no psoriasis.
    Neither are on beta blockers.
    As far as management is concerned, your guess is as good as mine, or more likely, better than mine!"

  4. Prof. Bhushan KumarMay 03, 2018

    In addition to the diagnosis considered by you – acanthosis nigricans can also present with the same picture before it spreads to other sites. Obesity you have mentioned. F/H of diabetes is usually present in these individuals.
    In addition to the factor of friction in the case of Muslims with lichenfied and pigmented lesions on the forehead atopy has been found to be an equally important factor.
    For this patient Keratolytics containing salicylic acid 6-10% or Tretinoin 0.05% application will help in addition to weight reduction.


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