Sclerodactyly is a tightening and thickening of the skin of the fingers. It can cause the fingers to curl inward and the hands to form a clawed shape.

Systemic scleroderma causes sclerodactyly, which is an autoimmune disease and a rare form of arthritis that affects fewer than 500,000 people in the United States. Not everyone with scleroderma will get sclerodactyly.

This article looks at the causes and symptoms of sclerodactyly, as well as the treatment options available to manage the condition.

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Sclerodactyly can cause the fingers and hand to form a clawed shape.

People with scleroderma may notice their hands become swollen and puffy before the onset of sclerodactyly. It may also become difficult to bend the fingers.

The skin may:

  • feel tight or stretched
  • get thicker
  • become harder
  • appear shiny or wax-like

Initial symptoms may:

  • appear and then go away from time to time
  • last for weeks or years
  • be worse in the morning

In rare cases, these symptoms will eventually advance to the point of sclerodactyly, where the hand forms a claw, and a person is unable to move their fingers.

Additionally, the underlying soft tissue may begin to waste away.

As noted earlier, sclerodactyly is caused by systemic scleroderma, an autoimmune disease. When a person has an autoimmune disease, their immune system attacks healthy body tissue after mistaking it for foreign invaders, such as bacteria or viruses.

In scleroderma, the body responds to a perceived attack by producing too much collagen, a protein found in the skin. Collagen gives the skin its strength and elasticity, and it also helps to replace dead skin cells.

It is thought that this overproduction of collagen occurs because the body believes there is an injury that needs repairing. This extra collagen can interfere with normal bodily function, causing the skin to become hard, leathery, and shiny.

The exact cause of scleroderma is unknown. There is a gene that makes some people more likely to get the condition than others, but this gene alone does not cause the disease.

Risk factors

The biggest risk factor for sclerodactyly is having scleroderma, an autoimmune condition that affects women more often than men.

There are several different types of scleroderma:

Localized scleroderma

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Raynaud's disease is one of the symptoms associated with limited scleroderma.

Symptoms of localized scleroderma usually only occur in a few places on the skin or muscles. In general, this condition is mild and rarely spreads. People with localized scleroderma do not usually develop systemic scleroderma.

There are two forms of localized scleroderma: morphea and linear scleroderma.

Morphea

Morphea is marked by waxy skin patches and can cause skin thickening. Over time, the patches may vary in size or disappear altogether.

Morphea most commonly occurs in people aged 20 to 50.

Linear scleroderma

Linear scleroderma often begins as an area of hardened skin. This form of scleroderma most commonly affects the arms, legs, neck, and forehead. In some cases, it can impact joint motion.

Linear scleroderma most commonly develops in children.

Systemic scleroderma

Also known as systemic sclerosis, systemic scleroderma is the form of scleroderma that can cause sclerodactyly.

This condition can affect:

  • blood vessels
  • food pipe
  • digestive tract
  • heart
  • joints
  • kidneys
  • lungs
  • muscles
  • skin

Systemic scleroderma can be diffuse or limited.

Diffuse scleroderma

In this form of systemic scleroderma, the skin can thicken at a rapid pace and affect a greater surface area.

Those who develop diffuse scleroderma are at an increased risk of developing sclerosis, a hardening of the body's internal organs.

Limited scleroderma

A more common form of systemic scleroderma, limited scleroderma causes slow and contained skin thickening, which typically affects the hands and face.

Internal damage can occur, but it tends to be less frequent and less severe than in diffuse scleroderma.

However, a condition called pulmonary hypertension is associated with limited scleroderma. Pulmonary hypertension is marked by narrowing of the blood vessels in the lungs, which causes shortness of breath.

Limited scleroderma is also known as CREST syndrome, which represents the first letters of a range of symptoms associated with limited scleroderma.

CREST stands for:

Several of the above symptoms, such as calcinosis and telangiectasias, can also affect some people with diffuse scleroderma.

There is no cure for sclerodactyly. Treatment aims at reducing symptoms and improving quality of life for those with the condition.

Treatment is most effective when it is started in the early stages of sclerodactyly, highlighting the importance of early action.

Available treatment options include:

Physical therapy and occupational therapy

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Physical therapy may be beneficial to some people with sclerodactyly.

Hand exercises may help some people with early symptoms of sclerodactyly, such as swelling or tight skin. The exercises used are similar to those prescribed for people with arthritis.

Some therapists are specially trained to make hand casts. These casts can be worn all the time to ensure that if the hands harden, they take on a less restrictive shape than the claw-like shape typical of sclerodactyly.

This may help people with the condition carry out their daily activities with greater ease.

Therapists may also recommend the use of hot wax machines to warm the hands and reduce pain and stiffness.

Ultraviolet (UV) light

Using UV light therapy may help break down the hardened collagen in the skin tissue. A portion of UV light, known as ultraviolet A1 (UVA1), is responsible for this effect.

UVA1 acts on certain collagen-producing cells in the skin called fibroblasts. The UVA1 light leads the fibroblasts to break down the extra collagen that causes the skin thickening and tightness.

Some research suggests people with sclerosing skin diseases will require between 20 and 40 exposures to UV light before they see results. Long-term side effects are still unknown.

Surgery

Those with sclerodactyly and other symptoms of systemic scleroderma that affect the hands or feet may wish to consider surgical treatment.

Although surgery cannot completely cure scleroderma, it can provide symptom relief and increase hand movement.

While there is no cure for sclerodactyly, there are several treatment options available to treat its symptoms and improve a person's quality of life.

Receiving early treatment is key to preventing the hands from forming a claw shape, thus reducing hand function.

Those who think they may have scleroderma or sclerodactyly should speak to their doctor as soon as possible.