What Is Dermatomyositis?

Calcinosis

Calcinosis is the word used to describe the hard bumps that can appear under your skin or in the muscle. These are caused by calcium deposits. Not everyone gets them, but they can appear as late as one to three years (or longer) after the disease starts, and they’re more common in children than adults.

Dermatomyositis Diagnosis

Your doctor has several tools they can use to figure out if you have dermatomyositis, including:

Blood tests. Blood tests can check for high levels of certain enzymes that tell if your muscles are damaged, even if you don’t feel any muscle symptoms. Your blood can also show if you have any specific antibodies produced by your immune system (called autoantibodies). This information could help your doctor choose the right treatment.

Chest X-ray. This can show whether your lungs are damaged, a possible sign of dermatomyositis.

Electromyography.This test looks at the electric output of your muscles to see where the weakness is. Your doctor puts a thin needle with an electrical impulse into your muscle, then records how much electric output there is when you tighten and relax.

Magnetic resonance imaging (MRI). Your doctor will use this to see where your muscles are inflamed.

Skin or muscle biopsy.By removing a small part of your skin or muscle and looking at it under a microscope, your doctor can see if you have dermatomyositis. Biopsies can also rule out other diseases, like lupus. 

Dermatomyositis diagnostic criteria

In order for your doctor to make an official dermatomyositis diagnosis, you have to meet certain criteria. Except for amyopathic dermatomyositis, which is diagnosed differently, you must have at least one of these skin symptoms for diagnosis:

• A red or purple rash with swelling on your upper eyelid, called a heliotrope rash
• Dilated capillaries (tiny blood vessels) at the skin folds around your fingernails, appearing as small red dots, called periungual telangiectasias
• Red or purple hardened areas of skin or areas where the skin seems to be wearing away on the top parts of your finger joints or over your elbows or knees, called Gottron’s sign or papules
• Red rashes, sometimes raised, that look like they’re forming a “shawl” pattern over your shoulders, arms, and upper back. It’s also like a V-shape over the front of your neck and chest, reaching down to over the outside of your hip. This is called the shawl sign, V sign, or holster sign.
• A skin biopsy that shows lessening density or thickness in your capillaries and damage in the small blood vessels

In addition to having something in the list above, you also must have at least four of these:

• Muscle weakness in both your shoulders, upper arms, hips, and thighs, and your trunk
• Muscle pain when you try to grasp something
• Spontaneous pain – sudden pain without a noticeable cause
• Signs that there is an inflammation in your body, such as fever
• Arthritis that doesn’t destroy the joint
• Blood tests that show high levels of certain enzymes or autoantibodies that are specific to the disorder, or show that there’s inflammation somewhere in your body
• EMG test that shows specific muscle changes
• Muscle biopsy findings that show muscle damage caused by inflammation

Dermatomyositis Treatment 

You can’t cure this condition, but you can treat your skin and muscle symptoms. You may need to see more than one doctor or medical professional, depending on your symptoms. Any of the following specialists might play a part in your care:

• Internist (for general care)
• Rheumatologist (for problems with connective tissues like muscles and joints)
• Immunologist (for immune system problems)
• Physical therapist (to help you regain muscle strength)
• Speech therapist (to help you with speaking or swallowing problems due to muscle weakness)
• Dietitian (for help finding easy-to-eat foods when swallowing is hard)

The most common medications for dermatomyositis include:

• Corticosteroids, such as prednisone. You take these by mouth or through an IV.
• Corticosteroid-sparing agents. These help lower the amount of corticosteroid you need, and that cuts down on your side effects. They include azathioprine (Azasan, Imuran), methotrexate (Trexall) and mycophenolate mofetil (CellCept).
• Immunosuppressant drugs, such as azathioprine and methotrexate. These help reduce your inflammation if prednisone doesn’t work.
• Rituximab (Rituxan) is a rheumatoid arthritis medication.
• Antimalarial medicines like hydroxychloroquine (Plaquenil) treat rashes that won’t go away.

Dermatomyositis Complications

Dermatomyositis can lead to complications. If you notice any signs of the following, let your doctor know right away:

Breathing problems. These can happen when the condition affects your chest muscles.

Muscle atrophy. Your muscles may get smaller and weaker.

Contractures. Your muscles can tighten and shorten, causing contractions such as curled fingers or wrists.

Raynaud’s phenomenon. This condition can make your fingers, toes, cheeks, nose, and ears turn pale if they’re in a cold environment.

Lupus, rheumatoid arthritis, scleroderma, Sjogren’s syndrome, and other diseases that affect the connective tissue. People with dermatomyositis can have diseases like this at the same time.

Esophageal disease. Dermatomyositis can cause the muscles around your esophagus, the palate, and the back of your tongue to weaken. This can make it hard for you to swallow, which can lead to:

• Aspiration pneumonia, which happens when you inhale food or drink and it causes an infection in your lungs
• Malnutrition, because it’s too hard to get enough healthy food

Heart disease. Dermatomyositis can affect the heart muscle, causing inflammation. 

Lung disease. Just as dermatomyositis can affect the heart muscle, it can also affect lung tissue, causing interstitial lung disease.

Cancer. Some types of cancer, particularly non-Hodgkin's lymphoma, as well as lung, pancreatic, stomach, colon, and ovarian cancer, can happen if you have dermatomyositis. The risk is highest the first year you have it and evens out after 5 years.

How to Prevent Dermatomyositis

Since no one knows what causes dermatomyositis, there's no way you can prevent it.

Living With Dermatomyositis

There’s no cure for dermatomyositis, and for a small number of people (about 5%), it can be fatal. Up to 20% of people with dermatomyositis go into long-term remission, which means they have no symptoms of the disease at all.

In addition to your medical treatment, there are some things you can do to help your condition:

• Wear sunscreen with an SPF rating of at least 50 and sun-protective clothing whenever you go outside. The sun can make the rash worse.
• Don’t use tanning beds because the UV rays can be harmful to your skin.
• Try to stay active so you can maintain or strengthen your muscles.
• Rest when you need to.
• Acknowledge your feelings about having dermatomyositis. It may be helpful to join a support group or see a therapist.
• Do your prescribed exercises from therapists if you have any and speak to the therapist if you have trouble doing them.
• See your doctor regularly so they can monitor your progress.

Takeaways

Dermatomyositis is a rare disorder that affects your skin, muscles, and blood vessels. If you have dermatomyositis, you may develop skin rashes, and you might have muscle weakness and pain and joint pain – depending on which type of the disorder you have. It can affect people of any age, but it’s most commonly diagnosed in children from ages 5 to 15 and adults from 40 to 60. No one knows what causes it.

What is a heliotrope rash?

A heliotrope rash is a red or purple rash and swelling on or around the upper eyelid.

What is a shawl sign in dermatomyositis?

A shawl sign in dermatomyositis is a specific pattern the rash makes over your shoulders, arms, and upper back. 

What is the V sign in dermatomyositis?

A V sign is the rash making a V-shape over the front of your neck and chest, reaching down to over the outside of your hip.

Can you live a full life with dermatomyositis?

It’s hard to tell how long someone with dermatomyositis will live. About 5% of people with the disorder die within the first year, but more than 95% were still alive more than 5 years after they were told they have it. A lot depends on if they develop complications, like pneumonia or cancer.

What should you avoid with dermatomyositis?

People with dermatomyositis must avoid sun exposure so they don’t get more skin damage.