What is the Difference Between Dermatomyositis and Polymyositis?

Dermatomyositis and polymyositis are closely related conditions involving inflammation of connective tissue in the body. In polymyositis, the muscles are involved, and in dermatomyositis, both the muscles and the skin become inflamed. Patients diagnosed with dermatomyositis and polymyositis have a number of treatment options available to manage the conditions, but the chronic illness will linger for life, in varying degrees of severity. Patients may need to make some lifestyle modifications and adjustments to stay as healthy as possible while managing the disease.

These conditions are autoimmune in origin, with the body identifying normal proteins inside the connective tissue as foreign and attacking them. This leads to inflammation and a gradual breakdown of the tissue over time. Symptoms of dermatomyositis and polymyositis include muscle weakness, difficulty breathing, and fatigue, all associated with damage to the muscles. In patients with dermatomyositis, a rash appears as well, indicating involvement of the skin. A tell-tale rash across the knuckles is an especially common clinical sign.

Testing can be used to determine the extent of the damage and collect information about the patient's general level of fitness for the purpose of developing an appropriate treatment plan. Over time, dermatomyositis and polymyositis can lead to disabling impairments as the muscles grow progressively weaker. The earlier the condition is identified, the better the prognosis for the patient, as patients can start treatment before permanent damage sets in.

Rest to allow the muscles to recover is one aspect of treatment. In addition, patients may be prescribed immunosuppressive drugs to limit damages caused by the immune system. It may be necessary to stay on these drugs for life, requiring patients to be careful about injuries and infections, as their bodies will be less able to fight off common infectious organisms, and injuries will tend to heal more slowly. Once patients are stabilized, they may benefit from gentle physical therapy and periodic rests if they experience flareups.

There appear to be some genetic components in dermatomyositis and polymyositis, and these conditions are more common in women than men. People with a family history of either condition should watch closely for early warning signs of symptoms, and may want to consult a rheumatologist or immunologist to discuss their family history and potential treatment options. These conditions can ultimately qualify people for disability benefits, as they may eventually be unable to work as a result of fatigue and muscle weakness.