Dermatomyositis (dur-muh-toe-my-uh-SY-tis) is an uncommon inflammatory disease marked by muscle weakness and a distinctive skin rash.
Dermatomyositis affects adults and children alike. In adults, dermatomyositis usually occurs from the late 40s to early 60s. In children, the disease 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 remission — when symptoms improve spontaneously — may occur. Treatment can clear the skin rash and help you regain muscle strength and function.