A:

It’s not known why dermatomyositis develops. It’s a condition marked by rash and muscle inflammation. Muscles become weak and may be sore. Other organs, including the lungs and joints, can also be inflamed.

Doctors usually suspect dermatomyositis based on a combination of symptoms (especially the typical rash over the eyes and upper chest, along with muscle weakness), physical exam, blood tests and special testing of muscle function. A biopsy is usually required to confirm the diagnosis. There are muscle disorders that can closely mimic dermatomyositis. These disorders may be less responsive to treatment. So it is important that the diagnosis of dermatomyositis is clearly established.

Initial treatment typically includes high doses of corticosteroids for 4 to 8 weeks, followed by a gradual reduction in dose. Doctors recommend antibiotics only if there is an associated infection, such as pneumonia.

Not everyone responds to corticosteroids. And some that do respond continue to need a high dose. High doses of corticosteroids have serious side effects. In these cases, there are other good treatment choices, including:

• Methotrexate, azathioprine, or other immunosuppressive medicine can often control inflammation, reduce disease activity and improve muscle strength.
• Intravenous immunoglobulin (IVIG). Infusions of these proteins have been found to help many people with dermatomyositis. But they’re generally reserved for those not responding to immunosuppressive medicine.
• Combinations of these treatments. For example, methotrexate and azathioprine are sometimes prescribed together to get muscle inflammation under control.
• Non-steroidal anti-inflammatory drugs (NSAIDs), hydroxychloroquine or topical corticosteroid treatments. They may improve the joint pain and rash.

In up to 10 to 15% of cases, dermatomyositis may be associated with cancer. This is a particular concern in older people or when usual treatment is not effective. Some doctors recommend only the screening tests that are ordinarily appropriate for age and gender even if dermatomyositis is present. But others will also order CT or MRI scans of the chest, abdomen and pelvis to look for a tumor. The best approach is not clear. But your sister should review this possibility with her doctors if she hasn’t already.

The specific problems your sister is having should determine which of these treatments might be best. Or whether other evaluation might be in order. By reviewing the details of her symptoms, exam and test results, her doctor can help her choose the best treatment beyond what she has already received.