What are the other Names for this Condition? (Also known as/Synonyms)

• Keratolysis Plantare Sulcatum
• Ringed Keratolysis
• Sweaty Sock Syndrome

What is Pitted Keratolysis? (Definition/Background Information)

• Pitted Keratolysis is a bacterial infection that is characterized by peeled white skin and pit-like craters on the soles of the feet, particularly on the pressure-bearing areas. The condition is termed superficial because it only involves the stratum corneum i.e., the outer skin layer (the non-living layer of the epidermis)
• Pitted Keratolysis may develop from a combination of factors, including hot-humid weather, regular use of synthetic boots, and excessive sweating, causing bacterial overgrowth. With adequate treatment, which includes antibiotic therapy and proper foot care, Pitted Keratolysis is known to resolve completely within a few weeks

Who gets Pitted Keratolysis? (Age and Sex Distribution)

• Most cases of Pitted Keratolysis are observed in adults, but children may also be affected
• Both males and females are affected. A greater number of cases are reported in males due to the nature of their work/occupation
• Worldwide, there is no racial or ethnic preference observed. The condition is more common in the tropics

What are the Risk Factors for Pitted Keratolysis? (Predisposing Factors)

The risk factors for Pitted Keratolysis include:

• Hot and humid conditions
• Individuals who frequently walk barefoot
• Hyperhidrosis, or excessive sweating, especially of the hands and feet
• Regularly wearing synthetic (and covered) footwear that restrict adequate ventilation to the feet, such as rubber boots
• Wearing wet shoes
• Having thickened skin on the palms of the hands and soles of the feet
• Advancing age
• Poorly-controlled diabetes
• Individuals with weak immune systems

Individuals in the following occupations have a higher risk for Pitted Keratolysis:

• Agriculture
• Armed services
• Certain industries and factories, including mining
• Fishing industry
• Sailing
• Sports
• Working in spas that offer foot care and pedicure

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Pitted Keratolysis? (Etiology)

• Pitted Keratolysis is a low-grade infection that is the result of bacterial overgrowth due to certain favorable factors such as excess sweating, moistness of skin, and warmth. The characteristic pits are a result of destruction of the superficial skin layer, the stratum corneum
• Hence, individuals in certain trades/occupations, such as farmers and farm hands, sportspersons and athletes, military personnel, and factory workers, have an increased risk for Pitted Keratolysis

The following pathogens have been implicated in the development of the condition:

• Actinomyces keratolytica
• Corynebacterium species (most commonly implicated bacteria)
• Dermatophilus congolensis
• Kytococcus sedentarius
• Streptomyces

Infrequently, the following pathogenic bacteria are noted:

• Acinetobacter
• Clostridium
• Klebsiella
• Pseudomonas

What are the Signs and Symptoms of Pitted Keratolysis?

The signs and symptoms of Pitted Keratolysis may include:

• Presence of whitish skin that “peels off” from the soles
• Numerous crater-like (circular) pits that border each other
• The condition appears more pronounced when the feet are wet
• In a vast majority, the soles of thee feet are involved. But uncommonly, the palms of the hands (including the fingers) may also present Pitted Keratolysis
• Mostly, the pressure-bearing surfaces are initially affected; however, the entire surface of the feet may be affected
• Smelly feet because of sulfur compounds that are released by bacterial overgrowth
• Pain is not observed, but individuals may have discomfort and itchiness, particularly when they stand or walk

How is Pitted Keratolysis Diagnosed?

A diagnosis of Pitted Keratolysis may involve the following exams and procedures:

• Physical examination of the individual and medical history evaluation; in many cases, the dermatologist may diagnose the condition clinically (through a visual examination and assessment of signs and symptoms, including one’s nature of occupation)
• Culture of skin scrapings, if needed, to rule out a fungal infection
• Dermoscopy: Dermoscopy is a diagnostic tool where a dermatologist examines the skin using a special magnified lens
• Wood’s lamp examination: In this procedure, the healthcare provider examines the skin using ultraviolet light. It is performed to examine the change in skin pigmentation
• Skin biopsy, if required: A skin tissue biopsy is performed and sent to a laboratory for a pathological examination. The pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis

A differential diagnosis may be undertaken to exclude other skin conditions that present similar signs and symptoms. These may include:

• Athlete's foot
• Erythrasma
• Hyperhidrosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Pitted Keratolysis?

The possible complications due to Pitted Keratolysis include:

• Emotional stress
• Superimposed bacterial and fungal skin infections
• Difficulty in wearing footwear until the condition heals
• Recurrence of the condition following treatment; typically, recurrence rates are high if the predisposing factors are not well addressed
• Treatment complications

How is Pitted Keratolysis Treated?

The treatment measures available for Pitted Keratolysis include:

• Topical antibiotic therapy, which may include clindamycin, erythromycin, mupirocin, or econazole
• Oral antibiotics may be necessary in some cases
• Use of suitable antiseptics that contain benzoyl peroxide to prevent overgrowth of bacteria, if necessary
• Use well-adjusted and breathable non-synthetic shoes/footwear that are comfortable and friction-less
• Wear cotton socks and change socks frequently
• Proper foot care and hygiene - keeping feet clean and dry

How can Pitted Keratolysis be Prevented?

Pitted Keratolysis may be prevented by considering the following steps:

• Maintaining good personal (body and feet) hygiene
• Wash feet daily with antibacterial soap
• Use non-synthetic and well-fitting shoes and sandals; limit the wearing time of boots and other closed (non-breathable) footwear
• Use socks made of cotton or wool
• Prefer open-toed footwear than occlusive ones
• Dry shoes after wearing them; open out socks after use and place them in a well-ventilated area
• Avoid walking barefoot regularly in hot-wet environments
• Take adequate care of one’s feet - keep them clean and dry
• Decrease sweating through the use of aluminum chloride antiperspirants
• Avoid sharing shoes, socks, or towels with others

What is the Prognosis of Pitted Keratolysis? (Outcomes/Resolutions)

• The prognosis of Pitted Keratolysis is generally excellent with adequate treatment. The condition may resolve in about 2-3 weeks
• However, Pitted Keratolysis may recur if the underlying risk factors are not addressed appropriately

Additional and Relevant Useful Information for Pitted Keratolysis:

The following DoveMed website link is a useful resource for additional information:

https://www.dovemed.com/healthy-living/skin-disorders/