Dermatomyositis

Dermatomyositis (dur-muh-toe-my-uh-SY-tis) is a condition in which swelling and irritation, called inflammation, attacks the body's tissues. Dermatomyositis causes muscle weakness and a skin rash.

The condition, also called an autoimmune condition, isn't common. It can affect adults and children. In adults, dermatomyositis most often happens in the late 40s to early 60s. In children, it most often appears at ages 5 to 15.

There's no cure for dermatomyositis. But treatment can improve muscle strength and help muscles work better. Treatment also can help clear the skin rash.

The symptoms of dermatomyositis can appear at once or they can come on over time. The most common symptoms include:

• Skin changes. A violet-colored or dusky red rash appears, most often on the face and eyelids and on the knuckles, elbows, knees, chest and back. The rash may be harder to see on Black skin or brown skin.

  The rash is often the first sign of dermatomyositis. It may hurt and itch. There also may be small bumps on the hands, mainly near the knuckles.

  Children also may get white spots on their skin from calcium deposits, called calcinosis.

• Muscle weakness. Muscle weakness involves the muscles closest to the center of the body, called the trunk. This includes the muscles in the hips, thighs, shoulders, upper arms and neck. The weakness affects both the left and right sides of the body. It tends to get worse over time.

Some people with dermatomyositis have only the skin symptoms. But muscle weakness may start years later.

Make an appointment with a healthcare professional if you get muscle weakness or a rash with no known cause.

Experts don't know the exact cause of dermatomyositis. Having certain gene changes may make people more likely to get the condition.

People assigned female at birth have a higher risk of dermatomyositis than do people assigned male at birth.

Possible complications of dermatomyositis include:

• Trouble swallowing. The condition may affect the muscles in the tube that carries food from the throat to the stomach, called the esophagus. This can lead to trouble swallowing, called dysphagia. Trouble swallowing may cause weight loss and not getting enough nutrition.
• Aspiration pneumonia. Trouble swallowing also may cause breathing food or liquids, including saliva, into the lungs. This is called aspiration and can lead to pneumonia.
• Breathing problems. Dermatomyositis may affect the chest muscles. This can cause breathing issues, such as shortness of breath. If breathing is affected enough, it can cause failure of the system that allows breathing, called respiratory failure.
• Calcium deposits. These can happen in the muscles, skin and connective tissues as the disease gets worse. These deposits are more common in children with dermatomyositis.

Linked conditions

Dermatomyositis might cause other conditions or raise the risk of getting them, including:

• Raynaud's disease. This condition causes the fingers, toes, cheeks, nose and ears to turn pale, purple or red in response to cold temperatures or stress. Color changes may be harder to see on Black skin or brown skin. The condition also may cause numbness and tingling.
• Other diseases. Other autoimmune conditions, such as lupus, rheumatoid arthritis, scleroderma and Sjogren syndrome, can happen with dermatomyositis.
• Cardiovascular disease. Dermatomyositis may cause the muscular walls of the heart to become inflamed, called myocarditis. A small number of people who have dermatomyositis may get congestive heart failure and irregular heart rhythms, called arrythmias.
• Lung disease. A condition called interstitial lung disease may happen with dermatomyositis. Interstitial lung disease is a group of conditions that cause scarring of lung tissue. Called fibrosis, the scarring makes lung tissue stiff and thick. This makes it hard for the lungs to expand and fill with air.
• Cancer. Dermatomyositis in adults has been linked to a higher risk of getting certain types of cancer. Ask your healthcare professional what cancer screenings you may need.