Pitted keratolysis

Dr Keith Hopcroft continues our series of fascinating but often unrecognised conditions

The case

‘You've got to do something about his smelly feet, doctor.' This is usually the battle cry of a woman dragging her reluctant male other half for an appointment – and, typically, precipitates a script for an anti-fungal plus some simple hygiene advice. On this occasion, though, it was a mother and her teenage boy. He had spent a long weekend at a music festival, so his feet had been encased in trainers even longer than usual – and opportunities to freshen up had been minimal. His feet were, indeed, pretty pungent, so I kept the examination to a minimum. This revealed a soggy bilateral rash on the weight-bearing areas of each sole. He was otherwise well and – apart from the smell – the rash was causing no symptoms.

The diagnosis

A cursory glance is usually all you need to make this diagnosis – provided you've heard of it, and seen it before. He had pitted keratolysis, a bacterial infection of the feet that is usually caused by corynebacterium.

Typical features

This problem commonly affects those whose feet naturally tend to sweat a lot – or do so because they are encased in non-aerating shoes. So soldiers, athletes and trainer-loving adolescents are high-risk groups. The result is macerated skin over the pressure areas with the characteristic pits in the skin – plus the unpleasant odour. Rarely, patients complain of mild discomfort. Even more unusually, the infection can spread to the palms.

Treatment

Topical antibiotics are the first-line treatment. In resistant or severe cases, oral treatment – typically erythromycin – is required. To prevent recurrence, the patient should observe basic hygiene rules and wear footwear that allows the feet to ‘breathe'. True hyperhidrosis should also be treated – usually with aluminium chloride hexahydrate solution.

Issues for the GP

It's tempting to assume that this type of presentation will simply represent sweaty, fungal-infected feet. In which case, resolution may be delayed because of the inappropriate use of antifungals.

Take-home point

The smell may tempt you to avoid any examination – resist this, because the briefest glance will provide the diagnosis and potentially alter your management.

Dr Keith Hopcroft is a GP in Essex

The PCDS was formed in 1994 by a group of GP skin specialists who recognised the need for a forum for GPs in the UK and Ireland to exchange views on primary care dermatology, hone skills and develop clinical research.
The society also provides a voice and support forum for GPSIs in dermatology.
Our key objectives are:
• To provide an innovative forum for GPs and GPSIs with
a common interest in dermatology to exchange views and
ideas, encourage research, improve patient management and promote education both for the GP and the healthcare team.
• To encourage an interest in and provide an arena to promote and establish a clearer understanding of dermatology in primary care.
• To create wider awareness and appreciation of the benefits of shared care and to encourage strong links with specialist groups such as the British Association of Dermatologists (BAD)
The Society holds a series of educational meetings around the country from dermoscopy to surgical training to general dermatological subjects, all delivered by both GPs and consultant dermatologists.