Punctate or pitted keratolysis

This is a condition characterised by multiple tiny holes on the top layer of the skin mainly on the soles of the feet. It can also be found between the toes, but usually affects pressure areas, such as the ball of the foot, heels and the pads of the toes.

Often it is accompanied with a distinctive smell.

What causes it?

Puncate or pitted keratolysis is thought to be caused by bacteria. Several species of bacteria are responsible including corynebacteria, Dermatophilus congolensis, Kytococcus sedentarius, actinomyces and streptomyces.

The small holes, or ‘pitting’ are due to the horny cells (stratum corneum) being destroyed by protease enzymes produced by the bacteria. This process is fed and exacerbated by moist conditions meaning that this condition is often found on sweaty feet.

The bad smell is due to sulfur compounds produced by the bacteria – thiols, sulfides and thioesters.

Who can develop it?

This condition is experienced more by men than women. Any profession where you are constantly on your feet and footwear is worn for extended periods makes the wearer prone to developing it. Examples are soldiers, farmers, industrial workers and fishermen but this list is by no means exclusive.

What is likely to make it worse?

This list isn’t exhaustive but these are some of the main influencers –

• Hot, humid weather
• Occlusive, fully enclosed footwear, such as rubber boots or vinyl shoes
• Excessively sweaty feet (hyperhidrosis)
• Thickened skin of the soles of the feet (keratoderma/hyperkeratosis)
• Diabetes mellitus
• Aging
• Immunodeficiency

What does it look and smell like?

Puncate keratolysis usually results in very smelly feet This is caused by infection of the soles of the feet. Either the forefoot or the heel or both become white with clusters of punched-out pits.

The appearance is clearer and more dramatic when the feet are wet, such as after a bath or shower, swimming or long periods in the same shoes.

It can affect the fingers but this is very rare. There is a variant where there are more diffuse or wide spread, red areas on the soles of the foot.

The key things to look for are –

• Mainly affects the soles, forefoot, the heel and pads of toes or all three. Palms are very rarely infected.
• Presents as  whitish skin surface with clusters of multiple, fine punched-out pits.
• Pits can often join together to form larger, crater-like lesions.
• A variant presents with diffuse red areas on the soles of the feet
• Strong foot odour.

Why would you visit a Podiatrist?

The pits can present a striking and worrying appearance to the soles of the feet, but they don’t usually present with other symptoms such as pain. Occasionally, in chronic conditions, there  can be some itching and soreness associated on walking or standing.

The usual reason for concern is the strong smell that accompanies this condition.

A Podiatrist is trained to recognise this condition but if there is any doubt, skin scrappings and culture are possible to confirm which bacteria are involved.

How is it treated?

There are a number of topical anti-biotics and anti-septics that can be successfully applied, but these are normally only accessed through your GP.

Fucidic acid cream (or Fucidin) can be applied topically and if this fail, Clindamycin can be taken orally. Other medications are available and this would need to be discussed with your GP to decide the best treatment on an individual basis.

How can I prevent it or prevent it reoccurring?

Pitted keratolysis can recur quickly unless the feet are kept dry. the following are some ideas and steps to take to prevent that –

• Wear boots for as little time as possible
• Wear socks that allow effective absorption of sweat, ie cotton and/or wool
• Wear open-toed shoes/sandals whenever possible
• Wash feet with soap/detergent or antiseptic wash twice daily
• Apply antiperspirant to the feet regularly
• Do not wear the same shoes two days in a row allowing them to dry out
• Nevershare footwear or towels with others.

If you would like more information or to make an appointment with one of our Podiatrists, call 01628 773588 or email info@maidenheadpodiatry.co.uk.