Signs parents may notice
- A purple or reddish rash on the eyelids, sometimes with puffiness
- Red, scaly patches over the knuckles, elbows or knees
- Weakness when climbing stairs, getting up from the floor or lifting the arms
- Tiredness, frequent falls or wanting to be carried
- Muscle aches
- Changes in the skin around the fingernails
- Difficulty swallowing or a change in voice (needs prompt attention)
Tests that may be used
- Muscle enzyme blood tests (CK, LDH, AST, ALT, aldolase)
- MRI of the thigh muscles
- Myositis-specific antibody tests
- Nailfold capillaroscopy (looking at tiny blood vessels near the nails)
- Swallowing and breathing assessment
- Muscle biopsy or EMG in some children
What is juvenile dermatomyositis?
Juvenile dermatomyositis (JDM) is a rare autoimmune condition in which the immune system causes inflammation of the small blood vessels in the muscles and skin. This leads to a characteristic skin rash and muscle weakness. It most often begins between the ages of about five and ten years, but it can occur at any age in childhood. It is not contagious and is not caused by anything the family did.
Recognising JDM
The rash and weakness often develop gradually over weeks. Parents may first notice that their child tires easily, struggles with stairs, has difficulty getting up from sitting on the floor, or finds it hard to lift their arms to comb their hair. The skin changes, such as a purplish colour on the eyelids or red patches over the knuckles, may be mistaken for eczema or allergy at first.
Over time, some children develop small, hard deposits of calcium under the skin (calcinosis). Early treatment lowers the chance of this happening.
How is JDM diagnosed?
The diagnosis is based on the typical rash and muscle weakness, supported by blood tests showing raised muscle enzymes and an MRI showing muscle inflammation. Antibody tests help predict the course of the illness and guide treatment. Your child’s swallowing and breathing muscles, heart and lungs are also checked.
How is JDM treated?
The aim is to control inflammation quickly and fully, restore strength and prevent complications.
- Steroids are usually the first treatment and are often given intravenously at the start, then by mouth, with the dose reduced gradually.
- Methotrexate is commonly started at the same time to control the disease and allow steroids to be reduced.
- Hydroxychloroquine may help with skin disease.
- IVIG and other medicines, including other immunosuppressants or biological therapies, may be used if the disease is severe or does not respond.
- Physiotherapy helps rebuild strength and keep joints flexible.
Regular follow-up visits check muscle strength, skin, growth and the safety of medicines.
When to see a pediatric rheumatologist
If your child has muscle weakness together with a rash on the eyelids or knuckles, ask your child’s doctor about a pediatric rheumatology referral. Seek urgent care if your child has difficulty swallowing or breathing.
Treatment options that may be considered
- Steroids, often started intravenously
- Methotrexate
- Hydroxychloroquine for skin disease
- IVIG
- Other immunosuppressive or biological medicines when needed
- Physiotherapy
- Sun protection
When to seek medical help urgently
- Difficulty swallowing, choking or coughing during feeds or meals
- A weak voice or breathing difficulty
- Severe abdominal pain
- Rapidly worsening weakness
Questions parents often ask
Is JDM the same as muscular dystrophy?
No. Muscular dystrophies are inherited conditions in which muscles weaken because of a genetic change. JDM is an inflammatory condition caused by the immune system, and the muscle weakness usually improves with treatment.
Will my child get their strength back?
With early and adequate treatment, most children regain their muscle strength, although it can take several months. Physiotherapy plays an important role in recovery.
How long will treatment last?
Treatment is usually needed for at least two years, and sometimes longer. Medicines are reduced gradually once the disease has been inactive for some time.
Why is sun protection important?
Sunlight can worsen the skin rash and may trigger disease activity. Sunscreen, protective clothing and avoiding strong midday sun are recommended.
This page is general information and not a substitute for a consultation. Every child is different, and the right treatment depends on an individual assessment. Please do not start, stop or change any medicine without speaking to your child's doctor.