Dermatomyositis
Medically reviewed by Dr Ramani Arumugam, Consultant Rheumatologist ·
A rash on the eyelids or knuckles that will not settle, together with muscles that tire on the stairs, is a pattern I take seriously. Dermatomyositis is a rare autoimmune condition that affects the skin and the muscles, and sometimes the lungs. It is often treated as eczema or an allergy for months before anyone connects the skin with the weakness. My role is to make that connection early, check the organs that matter, and start treatment.
Dermatomyositis: understanding the condition
This one-page summary brings together the skin signs, the muscle symptoms, the tests and the treatment options. Tap the image to open it full size if the print is small on your phone.
View the full-size infographicUnderstanding dermatomyositis
Dermatomyositis is one type of myositis, a group of conditions in which the immune system attacks the body's own tissue. In dermatomyositis the targets are the skin and the muscles. The rash is what sets it apart from the other types. Some people have the rash with little or no muscle weakness. This is called amyopathic dermatomyositis, and it still needs a full assessment because the lungs can be involved.
The skin signs
- Heliotrope rash. A purple or dusky colour on the upper eyelids, often with swelling around the eyes.
- Gottron papules. Raised, scaly bumps over the knuckles and finger joints.
- V sign and shawl sign. A rash across the front of the neck and chest, or across the shoulders and upper back.
- Nail fold changes. Redness or thickening around the nails, with ragged cuticles.
- Scalp rash. Scaly and very itchy, and easily mistaken for psoriasis.
- Sun sensitivity. The rash often gets worse after sun exposure.
On brown and darker skin the rash can look dusky purple or brown rather than red, so it is easy to miss.
Why it happens
We do not know the exact cause. Dermatomyositis is an autoimmune condition and is not usually inherited, although some people carry genes that make autoimmune disease more likely. It most often starts in adults aged 40 to 60 and in children aged 5 to 15, and it affects women more often than men. It is not contagious.
How I reach the diagnosis
- Examination. I look closely at the eyelids, knuckles, nails, scalp, chest and back, and I test your muscle strength.
- Blood tests. Muscle enzymes such as creatine kinase (CK), and a myositis antibody panel. The antibody type helps me judge the risk to the lungs and the need for cancer screening.
- Muscle MRI or EMG. To confirm that the muscle is inflamed.
- Skin or muscle biopsy. A small skin sample can confirm the diagnosis. If the skin findings are typical, a muscle biopsy is often not needed.
- Lung checks. A chest scan and lung function tests, because lung inflammation can be silent at first.
- Cancer screening. In adults, dermatomyositis is linked to a higher risk of some cancers. I arrange screening that fits your age and risk.
What treatment looks like
There is no cure yet, but treatment can clear the skin, bring back muscle strength and protect the lungs.
- Corticosteroids. Usually the first step. I start at a dose that controls the inflammation, then reduce it slowly.
- Steroid-sparing medicines. Methotrexate, azathioprine or mycophenolate, which is often chosen when the lungs are involved.
- Hydroxychloroquine. For a rash that persists.
- Creams. Steroid or tacrolimus creams for the skin.
- IV immunoglobulin (IVIG). For severe disease, skin disease that does not settle, or trouble swallowing.
- Rituximab. An option when first treatments have not controlled the disease.
- Therapy. Physiotherapy to rebuild strength, and speech therapy if swallowing is affected.
Muscle strength often starts to improve over the first 6 to 12 weeks. The skin can take longer.
What you can do yourself
- Protect your skin from the sun every day. Malaysian sun is strong all year. Use a high-protection sunscreen, a hat and covering clothing. My sunscreen guide explains how to choose one.
- Take your medicines as prescribed. Never stop steroids suddenly.
- Stay active. Follow an exercise plan from a physiotherapist and rest before you are exhausted.
- Report new symptoms early. Breathlessness, a dry cough, or food sticking when you swallow.
- Keep your screening and follow-up appointments. They are part of the treatment.
- Look after your bones and your vaccinations. See osteoporosis and vaccination for autoimmune patients.
What the future holds
Many people do well with treatment and regain their strength. Some go into remission. Others need a low dose of medicine for the long term, and the skin can be slower and more stubborn than the muscles. The outlook depends mainly on whether the lungs are involved and whether a cancer is found, which is why I check both at the start and keep checking.
Some of the information on this page is adapted from Muscular Dystrophy UK: Dermatomyositis and Mayo Clinic: Dermatomyositis. It is general education and does not replace an individual medical assessment.
What dermatomyositis is
Dermatomyositis is a rare autoimmune condition that causes a typical skin rash together with muscle weakness. The rash appears on the eyelids, knuckles, chest and shoulders, and the weakness affects the shoulders, hips and thighs. It can also inflame the lungs, and in adults it is linked to a higher risk of some cancers.
Symptoms to look out for
A purple or dusky rash on the upper eyelids, often with puffiness
Raised, scaly bumps over the knuckles
A rash on the chest, neck, shoulders or upper back that worsens in the sun
An itchy, scaly scalp, or redness around the nails
Difficulty climbing stairs, getting up from a chair or lifting your arms above your head
Tiredness that is out of proportion to what you have done
Difficulty swallowing
Shortness of breath or a dry cough
Joint pain or swelling
In children, hard lumps of calcium under the skin
Why this matters to a rheumatologist
Dermatomyositis is more than a skin condition. The rash is the visible part of a disease that can also weaken the muscles, scar the lungs and, in adults, signal a hidden cancer. A rheumatologist looks at all of these together. I confirm the diagnosis, check the lungs and swallowing, plan the cancer screening, and choose treatment that controls the skin, the muscles and the lungs.
Signs I would like you to seek care for
For emergency symptoms please seek urgent or emergency care first rather than waiting for a WhatsApp reply.
New breathlessness or a dry cough that is getting worse
Difficulty swallowing, or choking on food or drink
Weakness that is getting worse quickly
A rash on the eyelids or knuckles together with muscle weakness
Painful ulcers on the fingers or over the joints
Unexplained weight loss, fever or night sweats
What a specialist review looks like
I examine your skin and nails carefully and test your muscle strength. I arrange blood tests, including a myositis antibody panel, and the lung checks and cancer screening that fit your situation. If a skin biopsy is needed I work with a dermatologist. Then I explain the findings in plain language and start a plan that treats the skin, the muscles and the lungs together.
Questions my patients often ask me
The most typical signs are a purple or dusky colour on the upper eyelids and raised, scaly bumps over the knuckles. A rash can also appear across the chest, shoulders and upper back, and it often worsens in the sun.
Speak with me
If you have a rash on your eyelids or knuckles and your muscles feel weaker than before, please do not wait. WhatsApp my clinic and we can help you decide whether a rheumatology review is the right next step.
Other conditions I treat
This page is for general education only and does not replace medical advice. Please consult a qualified healthcare professional for diagnosis and treatment.