The first choice of treatment for polymyositis and dermatomyositis is steroids, which are usually given in high doses to begin with. They can be given as tablets or injections. This should reduce the inflammation very quickly and settle muscle pain and the feeling of being unwell.
High doses of steroids can have side-effects so your doctor will reduce the dosage as quickly as possible. You may be given bisphosphonates, calcium tablets and vitamin D tablets to guard against osteoporosis.
Sometimes the inflammation can flare up when the steroid dosage is lowered. Your doctor may prescribe other drugs to help reduce the inflammation, for example methotrexate, azathioprine and ciclosporin. Cyclophosphamide may also be prescribed. A newer drug now being used is mycophenolate mofetil. These are all types of disease-modifying anti-rheumatic drugs (DMARDs), and you’ll need regular blood tests to check for any possible side-effects.
Occasionally the drugs mentioned previously don’t control the condition. A small number of people with severe muscle disease and complications have been treated with biological therapies like infliximab and rituximab. These work by blocking the process of inflammation.
Alert card – Steroids
When taking steroid tablets you must carry a steroid card, which records your dose and how long you’ve been taking them. If you become ill, or are involved in an accident in which you’re injured or become unconscious, it’s important for the steroid to be continued. The dose might also need to be increased because the treatment may prevent your body from being able to produce enough natural steroids in response to stress, as normally happens in this situation. Your doctor or rheumatology nurse can give you a steroid card, and they're usually available from pharmacies as well.
Infusions of immunoglobulin
Infusions of immunoglobulins may be given in severe cases. These are antibodies that stop your immune system attacking your body's own tissues. Infusions are given in hospital at monthly or 3-monthly intervals. You might feel a little unwell (as if you have flu) during the infusion.
Even severe cases of myositis usually respond well to treatment, though some people do need ongoing drug treatments to keep their condition under control.
Exercises and physiotherapy
It’s probably best to rest when your myositis is very active, but once it has calmed down you’ll need to start exercises. Aerobic exercise is especially important to help restore muscle strength and improve stamina. At first this should be done under the supervision of a physiotherapist. They’ll give you a tailored programme to suit your specific needs regarding pain relief and improvement in muscle function/rehabilitation.
If your child has dermatomyositis they’ll need more vigorous physiotherapy to prevent flexion contracture.
Some people with severe inflammation never fully recover but most people do, though it may take several months for your muscle strength to improve. It may take weeks or months for your body to repair your muscles and you may get tired more quickly than normal, so don’t worry if you’re not back to full strength straight away.
Read more about exercise and arthritis and looking after your joints when you have arthritis.