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.

Symptoms

The most common signs and symptoms of dermatomyositis include:

Skin changes. A violet-colored or dusky red rash develops, most commonly on your face and eyelids and on knuckles, elbows, knees, chest and back. The rash, which can be itchy and painful, is often the first sign of dermatomyositis.

Muscle weakness. Progressive muscle weakness involves the muscles closest to the trunk, such as those in your hips, thighs, shoulders, upper arms and neck. The weakness affects both the left and right sides of your body, and tends to gradually worsen.