Introduction

 Palmoplantar keratoderma is a term used to define a marked thickening of the skin on the palms and soles, either as a focal entity, or diffuse. Keratoderma can be inherited, acquired, and rarely, paraneoplastic; that is, secondary to an internal malignancy.

Aetiology

• Keratoderma is usually acquired, but can be inherited.
• The feet are generally more severely affected than the hands. Occasionally, keratoderma can affect other parts of the body.
• It can be difficult to differentiate between the different types of keratoderma, however, the management principles are similar.

 Clinical classification

 Keratoderma can be defined by its clinical appearance, although there is often overlap:

• Diffuse – the whole of the palmar or plantar skin
• Focal – the pressure points are more severely affected e.g. heel margins, and either side of the metatarsal arch
• Punctate – multiple small scattered lesions
• Striate – longitudinal involvement, especially along the fingers

Logical approach to management

 As stated earlier, keratoderma may be hereditary, with symptoms presenting in early childhood, or acquired when it presents in later life. Rarely can it be associated with malignancy.

 Hereditary keratoderma

• Diffuse – Clinically, the features can be difficult to distinguish, usually in infancy, of diffuse, yellow, thickened skin, affecting the palms and soles.
• Focal – ​Localised areas of painful  skin thickening, and sometimes blisters,over the pressure points, for example, which develop on the heel margins, and either side of the metatarsal arch of the feet. The palms of the hands are usually less severely affected though. Some people also have abnormalities of the fingernails and toenail.
• Striate – Characterised by linear abnormal skin thickening, running along a finger, and onto the palm. The soles can be affected too.
• Some inherited cases of focal and striate keratoderma can occasionally have unusual features, such as hearing impairment, sparse hair, and woolly hair with cardiac disease.
• Punctate
  • ​Presents with multiple, small, maculo-papular lesions on the palms and soles.
  • It is most common in young adults.
  • Distribution – Mainly the palms and soles, although a few cases predominantly affect the medial and lateral margins of the hands and feet.
  • Morphology – Lesions may be unusually shaped, firm and scaly, with spiny projections, or occasionally warty.

 Acquired

•  It’s more common than the inherited.
• Can be focal or diffuse.
• There are many causes including:

• • Moderate-severe callosities
  • Inflammatory – eczema, psoriasis and lichen planus
  • Infective – crusted scabies, syphilis, Reiter’s disease
  • Drugs
  • Systemic diseases – diabetes mellitus, thyroid disease, and malignancy
  • Chronic lymphedema
  • Keratoderma climactericum  characterised by abnormal skin thickening of the palms and soles in women of menopausal age, and associated with obesity and hypertension. It usually affects the sole of the feet around the margins of the heel, and under the metatarsal heads. The palms of the hands may be affected with discrete, centrally placed lesions. Patients present with erythema, hyperkeratosis, and painful fissures.

 Investigations

•  Most patients will not require investigation.
• In cases of acquired keratoderma, if an underlying inflammatory dermatosis, or other obviously benign condition (e.g. multiple callosities, keratoderma climactericum) is absent, consider:
  • Skin scrapings to send for testing to exclude tinea
  • Thyroid function test and fasting glucose levels in symptomatic patients
  • Though rarely, more detailed investigations if an underlying malignancy is suspected.

Management

•  Emollients 
  • ​A urea-based emollient, may be beneficial during the daytime, with a more greasy ointment overnight. If a cream which contains 10% urea, is not effective, it is possible to prescribe other urea-based preparations up to aconcentration of 25%.
  • Patient choice is important.
• Physical methods of scale removal, such as pumice stones, emery boards, and paring (with or without soaking in water). Some patients may benefit from referral to podiatry, if they are not capable of removing scale themselves, and/or if advice is needed to help relieve pressure from foot involvement.
• Other topical keratolytics, such as 5-10% salicylic acid in yellow soft paraffin. These need to be made up though, and can be very expensive.

                               Your feet mirror your general health . . . cherish them!