What To Know About Hyperkeratosis

Hyperkeratosis is a common condition that causes the outer layer of skin, or stratum corneum, to harden and grow thicker. It occurs due to an overgrowth of keratin cells that compose this layer. Causes include acquired conditions like injury or pressure on the skin or congenital conditions (present at birth).

Hyperkeratosis symptoms depend on the underlying cause of the condition. In most cases, it’s a standalone and primarily cosmetic issue that doesn’t cause additional problems. However, it can be a sign of a more serious condition, with certain types raising cancer risk.

Treatments vary and depend on the case and goals of therapy. That said, there are a number of ways to manage and prevent this condition.

Types of Hyperkeratosis

Hyperkeratosis encompasses many different conditions. Healthcare providers break hyperkeratosis down into two types based on the underlying cause: acquired and hereditary.  

Acquired Hyperkeratosis

This type of hyperkeratosis occurs due to pressure, injury, or other nongenetic diseases. Common forms of acquired hyperkeratosis include:

• Corns or calluses: Pressure and friction cause corns, which have a bubble-like core, and calluses (patches that are hard and thick).
• Eczema: This is a common autoimmune disorder that causes flaky, reddish skin and bumps, itchiness, and sores.
• Psoriasis: This autoimmune skin condition causes silvery or scaly skin and plaques—elevated, solid lesions (patches) of discolored skin.
• Lichen simplex chronicus: This skin condition that causes dry, thick, patchy scales. It's often caused by continual rubbing or scratching.
• Plantar hyperkeratosis: This range of conditions can cause areas of thick skin on the soles of the feet or palms.
• Lichen planus: This causes rashes and patches of small, itchy, purple bumps.
• Seborrheic hyperkeratosis: More common in older adults, seborrheic hyperkeratosis causes benign (noncancerous) growths to form on the skin.
• Warts: Warts are small, often painless bumps or growths caused by viruses, often the human papillomavirus (HPV).
• Actinic hyperkeratosis: This is a patch of hardened, scaly skin caused by sun exposure. It often affects the lips, ears, back of hands, forearms, scalp, and neck.

Hereditary Hyperkeratosis

Certain types of hyperkeratosis are due to gene mutations that cause an overproduction of keratin cells. Present at birth, these conditions include:

• Epidermolytic hyperkeratosis: This causes blisters and red skin (erythema) in infants, which become hardened and darker with age.
• Ichthyosis: This causes scaly skin and spots. X-linked ichthyosis almost exclusively affects males at birth, while lamellar ichthyosis affects the palms or soles of the feet.
• Keratosis pilaris: Keratosis pilaris causes harmless, small, rough bumps, typically on the upper arms or thighs.
• Multiple minute digitate hyperkeratosis: This benign condition causes many small, hard white or brown bumps.
• Focal acral hyperkeratosis: This causes yellow, waxy, or flesh-colored growths (papules) and patches of thickened skin.

Hyperkeratosis Symptoms 

Hyperkeratosis is characterized by thickened, tougher skin. However, the form this takes varies based on type.

Corns

Corns are round patches with a hardened center surrounded by more pliable tissue. Sometimes painful, they most often form on the toes. The center can be tough or spongy.

Calluses

A calluses is an area of hardened skin of even thickness caused by pressure. Sometimes painful, they most often affect feet or fingers.

Warts

Warts are raised, rough, smooth, circular, or oval-shaped bumps often seen on fingers or toes—though other parts of the body can be affected. They tend to be lighter or darker than the surrounding skin and are sometimes painful.

Itchy, Scaly Skin

Psoriasis, eczema, and some other hyperkeratosis-causing conditions cause itchiness and scaly skin. Large, gray scales are a feature of epidermoylotic and other ichthyosis conditions.

Lichen Planus 

Broad, flat bumps of hardened, discolored skin on the palms of the hands or feet are features of lichen planus. Other symptoms include scabby blisters, itchiness, and sores in the mouth or vagina.

Plaques

Along with scaly skin, psoriasis causes skin plaque, a painless, raised patch of hardened skin. Most often found on the elbows, scalp, knees, or back, these take different shapes or have no defined borders.

Keratosis

A keratosis is a hardened yellow, gray, or brown patch of elevated skin. Painless and noncancerous, they have a waxy exterior.

Papules

Clusters of papules—small, discolored bumps—are a feature of several conditions, including minute multiple and focal acral hyperkeratosis. In the latter case, they are waxy and yellow.

What Causes Hyperkeratosis? 

Hyperkeratosis occurs when the outer layer of the skin, or stratum corneum, produces too any keratin cells. These cells are composed of a fibrous, tough protein. This overproduction is either pressure-related—caused by pressure and friction on the skin—or due to inflammation in the body or a genetic condition.

Pressure-related hyperkeratosis arises from constant weight or pressing, injury, chafing, or chemical damage from exposure to harsh cleaners or soaps.

Non-pressure-related hyperkeratosis can be caused by an allergic reaction, autoimmune condition (in which the immune system attacks healthy cells), or genetic disorder. It can also arise as a side effect of certain medications or chemotherapy.

Risk Factors

While everyone is susceptible to hyperkeratosis, some are at increased risk. Risk factors include:

• Family history of hyperkeratosis or allergy
• Allergies
• Autoimmune conditions
• Frequent sun exposure
• HPV infection
• Manual labor
• Working with harsh cleaners or soaps
• Chemotherapy
• Smoking tobacco, excess alcohol use
• Obesity
• Diabetes
• Hypertension (high blood pressure)
• Stress

Diagnosis

The goal of diagnosis is for healthcare providers to detect the underlying cause of symptoms. They want to rule out other conditions that affect the skin, especially dangerous ones like basal or squamous cell carcinoma, two types of skin cancer. The diagnosis of hyperkeratosis may involve several steps, including:

• Medical history: The provider will ask about your symptoms, as well as any family history of skin issues, autoimmune diseases, allergies, medications, or other health conditions.
• Physical examination: The healthcare provider will evaluate affected areas, looking for signs of hyperkeratosis and other symptoms. They may use a special microscope called a dermoscope.
• Patch tests: To detect the causes of allergic reactions, you wear patches with small amounts of allergens for 48 hours, after which the provider checks your reaction.
• Biopsy: If cancer is suspected, the healthcare provider may scrape off a sample of affected skin and send it to a clinical laboratory for testing.

Hyperkeratosis Treatment

Since hyperkeratosis isn’t usually dangerous, the goal of treatment is cosmetic: to improve appearance and self-image. Individual approaches depend on the case and condition treated and include everything from medications to a range of dermatological treatments.

Prescription Medications

Your provider may prescribe a topical cream or oral medication to treat conditions like psoriasis and eczema. This might include:

• Corticosteroids like Nucort (hydrocortisone) or Alphatrex (betamethasone)
• Immunosuppressants like Neoral (cyclosporine) and Azulfidine (sulfasalazine)
• Topical calcineurin inhibitors like Envarsus XR (tacrolimus) or Elidel (pimecrolimus)
• Retinoids (derivatives of vitamin A)

Dermatological Procedures

Dermatologists, specialists in skin conditions, perform a range of treatments to physically remove areas of hyperkeratosis:

• Corn or callous removal: After numbing affected areas, the provider carefully cuts away corns or callouses (known as shave excision) or files them down.
• Chemical peel: Also known as chemexfoliations, chemical peels involve applying chemicals to affected areas to remove damaged or thickened skin and improve its appearance.
• Cryotherapy: The provider uses a very cold substance to freeze and remove warts or keratosis.
• Laser therapy: Directed laser beams cause scarring in affected areas, which can treat warts or other growths.
• Light therapy: Exposing ultraviolet B (UVB) rays from specialized lamps to affected skin helps treat eczema, psoriasis, and some other conditions.
• Skin graft: Providers can remove severe planus hyperkeratosis and graft skin from another part of the body to replace it.

Prevention

You can take measures to prevent hyperkeratosis and flare-ups of conditions that cause it, like eczema or psoriasis. This includes:

• Skincare: Use beauty products that help exfoliate (remove outer layers of skin) and are gentle on the skin. Avoid hot baths, which may inflame symptoms.
• Topical agents: Regularly apply emollients (skin moisturizers) and keratolytics like urea acid, salicylic acid, and lactic acid to affected areas.
• Clothing and footwear: Getting inserts or changing footwear to promote comfort can prevent callouses from forming. Wearing looser clothing can prevent chafing.
• Sun protection: Avoid direct sunlight by wearing hats, longer clothing, and sunscreen—or stick to the shade during the middle of the day.
• Stress management: Stress and anxiety can trigger some types of hyperkeratosis. Try exercise, meditation, or other relaxing activities to cope.
• Weight management: Since excess weight can raise the risk of psoriasis, eczema, and some other types, losing weight by adjusting diet or boosting exercise may help.

Complications

Most cases of hyperkeratosis aren’t signs of anything serious, though some types can raise the risk of more serious disease. If untreated, potential complications can include:

• Mental health effects: Living with a skin condition can affect self-image and self-esteem, raising the risk of conditions like depression and anxiety.
• Skin cancer: While most types don’t cause cancer, actinic hyperkeratosis can become cancerous.
• Scarring: Severe cases of hyperkeratosis can cause permanent scarring on the skin after symptoms have resolved.
• Infection: Frequently scratching scaly skin, as in eczema, raises the risk of bacterial or viral infections on the skin.

A Quick Review

Hyperkeratosis occurs when the outside layer of skin becomes tough and thick. This can be the result of pressure or friction on the skin or other conditions, such as eczema and psoriasis.

Healthcare providers treat this condition with everything from medications to dermatological procedures to remove affected areas.

Though most cases of hyperkeratosis aren’t a sign of anything serious, some types can develop into cancer or raise the risk of other complications. Lifestyle changes and adopting a skin care routine are among ways to manage this condition.