Dermatomyositis (dur-muh-toe-my-uh-SY-tis) is an uncommon inflammatory disease marked by muscle weakness and a distinctive skin rash.
The condition can affect adults and children. In adults, dermatomyositis usually occurs from the late 40s to early 60s. In children, it most often appears between 5 and 15 years of age. Dermatomyositis affects more females than males.
There's no cure for dermatomyositis, but periods of symptom improvement (remission) can occur. Treatment can clear the skin rash and help you regain muscle strength and function.