Frictional Dermatosis in a Courier Driver.

Frictional hypermelanosis is an uncommon finding in Caucasians. We report the unusual case of 56-year-old male courier driver who developed linear and patchy hypermelanosis of the back caused by the driver's seat. Histology has included other pathologies. Treatment of the asymptomatic hyper pigmentation was not warranted.

Frictional hypermelanosis is an uncommon condition. The clinical finding is characterised by asymptomatic, diffuse, brownish patches located mainly in the skin above bony prominences. Histologically, increased melanin content of the epidermis with or without pigment incontinence, sometimes with amyloid deposits, are characteristic [1].

Friction may have various reasons, such as rubbing skin repeatedly with scrub pads (loofah) or bathroom towels [1], using a washing agent (fifa) during bathing with vigorous friction [2], religious practices [3, 4], clothing [5].

A 56-year-old male patient presented with a linear asymptomatic brownish hyperpigmentation above the breast spine and in the sacral region (Fig. 1 & 2). He used to drive a van as a courier driver for 10 to 12 hours a day. He took no medications and reported no other known complaints or diseases. We took a skin biopsy that confirmed epidermal hypermelanosis and excluded hypermelanocytosis. Amyloid was absent. There was no inflammatory dermal infiltrate as well.

Figure 1

Linear hypermelanosis above the breast spine

Figure 2

Patchy hypermelanosis in the sacral region

Based on history, clinical presentation and histopathology the diagnosis of frictional dermatosis due to the driver’s seat was confirmed. No treatment was wanted.

Friction can cause hypermelanosis, lichenoid dermatosis and callus formation. Other causes of circumscribed hypermelanosis include heat, neurocutaneous dysesthesia, post-inflammatory hyperpigmentation, adverse drug reactions, melasma and radiotherapy [6-9].

In case of warranted treatment, ablative surgery, cryosurgery, and lasers have been used with mixed results [10].