Keratoderma (Palmoplantar Keratoderma)

What keratoderma is

The skin on the palms and soles is naturally thicker than elsewhere. In keratoderma, the outer layer (stratum corneum) builds up excessively, forming hard, yellowish plaques. It is a form of hyperkeratosis specific to the hands and feet.

Dermatologists describe the pattern:

Inherited keratodermas

Genetic keratodermas are caused by changes in genes for skin structural proteins (such as keratins) and usually appear in infancy or childhood. There are many types, including:

• Epidermolytic and non-epidermolytic PPK: diffuse thickening with a red border, often with excessive sweating
• Mal de Meleda: progressive, spreads to the backs of hands and feet
• Pachyonychia congenita: painful focal keratoderma with thick nails
• Striate PPK
• Syndromic types, associated with hearing loss, heart muscle disease, hair abnormalities or, rarely, esophageal cancer (tylosis)

A family history is often present. Genetic testing can confirm the type.

Acquired keratodermas

These develop in adulthood. Causes include:

• Skin diseases: eczema, psoriasis, lichen planus, pityriasis rubra pilaris
• Infections: fungal infection (athlete's foot, tinea manuum), crusted scabies, syphilis, HPV warts
• Keratoderma climactericum: thickening of the soles, especially the heels, in women around menopause, often with obesity
• Hormonal and metabolic: hypothyroidism, diabetes
• Medicines: some chemotherapy drugs (hand-foot syndrome), lithium, certain targeted cancer therapies
• Chemical exposure: chronic arsenic exposure
• Paraneoplastic: rarely, new keratoderma signals an internal cancer, such as lung, esophageal or stomach cancer
• Lymphedema and other circulatory problems
• Mechanical: friction and pressure (calluses), which are very common but localized

Symptoms

• Thick, hard, yellowish skin on palms or soles
• Painful cracks and fissures, especially in cold, dry weather
• Pain when walking or gripping
• Excessive sweating (hyperhidrosis) and odor, sometimes with secondary fungal or bacterial infection
• Nail changes in some types
• In children, difficulty walking or using the hands

Diagnosis

A dermatologist will look at the pattern, ask about age of onset, family history, medicines, occupation, menopause and other symptoms, and examine skin, nails, hair and teeth. Tests may include:

• skin scrapings for fungal infection
• skin biopsy
• thyroid function and other blood tests
• genetic testing for inherited types
• investigations for internal cancer when acquired keratoderma has no other explanation

Treatment

There is no cure for inherited keratodermas, but symptoms can be controlled well. Acquired keratodermas often improve when the cause is treated.

Skin care

• Soaking hands and feet in warm water for 10 to 15 minutes softens the skin
• Paring or filing the thickened skin with a pumice stone or file, or by a podiatrist
• Emollients applied generously and often, ideally under cotton gloves or socks overnight
• Keratolytic creams containing urea (10 to 40%), salicylic acid or lactic acid to break down thick skin

Prescription treatments

• Topical retinoids and vitamin D analogs
• Oral retinoids (acitretin) for severe inherited forms, with monitoring for side effects
• Antifungal treatment for fungal causes
• Treatment of eczema or psoriasis with topical steroids or other therapies
• Thyroid hormone for hypothyroidism

Practical measures

• Well-cushioned, well-fitting footwear and insoles to reduce pressure
• Managing sweating with antiperspirants or iontophoresis
• Treating cracks with protective dressings or liquid bandage
• Regular podiatry care

Frequently asked questions

What is keratoderma?

Keratoderma is abnormal thickening of the skin on the palms and soles. It can be inherited, starting in childhood, or acquired later from conditions such as eczema, psoriasis, fungal infection, menopause or hypothyroidism.

What causes thick skin on the palms and soles?

Common causes include repeated friction (calluses), eczema, psoriasis, fungal infections and menopause-related keratoderma. Inherited gene changes cause lifelong keratoderma. Rarely, new thickening in an adult is linked to internal cancer.

Is keratoderma hereditary?

Some types are. Inherited keratodermas are caused by gene changes, often passed down in families, and usually appear in infancy or childhood. Acquired keratodermas are not inherited and develop later due to other conditions.

How is palmoplantar keratoderma treated?

Treatment includes soaking and gently filing thick skin, regular emollients, and keratolytic creams with urea or salicylic acid. Severe cases may need prescription retinoids. Treating any underlying cause, such as fungal infection or hypothyroidism, often helps.

Can keratoderma be a sign of cancer?

Rarely. Keratoderma that appears suddenly in adulthood without another explanation can occasionally be linked to internal cancers, such as lung or esophageal cancer. A dermatologist may recommend further tests in that situation.