Treatment varies, depending on the type of myositis.
Idiopathic inflammatory myopathies. For polymyositis and dermatomyositis, doctors usually begin treatment with a corticosteroid drug, such as prednisone (sold as a generic) or methylprednisolone (Solu-Medrol, others). If this fails, methotrexate (Rheumatrex) or azathioprine (Imuran) may be added. Intravenous immunoglobulin (an injection of antibodies collected from blood donors) may be effective in cases that fail these other treatments. Other immunosuppressant medications may be recommended to treat dermatomyositis and polymyositis, including cyclosporine, rituximab, mycophenolate mofetil or cyclophosphamide. Unfortunately, there is no reliably effective treatment for inclusion body myositis, although corticosteroid treatment and immunosuppressive therapies (as with polymyositis and dermatomyositis) are often tried for at least several months. If treatment is effective, ongoing therapy may improve strength or prevent worsening weakness.
When myositis accompanies another autoimmune disease (such as SLE), treatment of the underlying disease may be helpful; otherwise, treatment of the myositis is similar to that of polymyositis and dermatomyositis.
Infectious myositis. If you have the flu, you should rest in bed and drink plenty of fluids. You also can take nonprescription medicines for fever and muscle aches. If you have trichinosis, your doctor may treat you with mebendazole (Vermox) or albendazole (Albenza), antibiotic drugs that kill the trichinosis parasites. In addition, you should rest and take nonprescription drugs for pain. Your doctor may also prescribe prednisone to reduce inflammation associated with the infection. For pyomyositis, your doctor may recommend drainage of the abscess by making an incision or by inserting a needle. In addition, he or she will prescribe antibiotics to fight the infection.
Benign acute myositis. Your child's doctor will prescribe medication for pain. No other treatment is necessary, because the illness usually gets much better within a few days.
Myositis ossificans. Your doctor may wait to see whether the bony lump disappears on its own. If it doesn't, he or she may recommend surgery to remove the lump.
Drug-induced myositis. Your doctor will discontinue any medication thought to be causing myositis. Medications called corticosteroids may help you to recover faster.