Muscle Weakness: Muscle weakness will affect the body in a symmetric fashion, and this typically occurs gradually over time. Muscles that tend to be affected are the neck, shoulders, hips and thighs. Patients will complain of general fatigue, lack of energy, and are typically unable to perform simple tasks such as climbing up the stairs, swallowing, or even lifting heavy objects. In more advanced stages of the disease, muscles can be tender when touched. Patients typically complain of muscle pain.

Skin Rashes: There are a variety of rashes that can develop in DM, on different parts of the body. The rashes are typically red, itchy, and sometimes covered in scales. Exposing the skin to sunlight can make the rash worse. Rashes are commonly seen on the: fingers (including the finger joints and around the fingernails), elbows, knees, upper eyelids, neck, upper chest, upper back, and scalp.

Interstitial Lung Disease: Approximately 15-30% of patients with DM, will develop interstitial lung disease. This causes inflammation and scarring of the lungs and can make it more difficult for oxygen from the air to enter the lungs. This makes it much more difficult to breathe.

Malignancy: The development of adult DM has been associated with cancer, as rates can vary from 10% to 50%. Some of the cancers that have been identified include: ovarian cancers, colon cancers, breast cancer, lung cancer, gastric cancer, pancreatic cancer, and lymphomas (non-Hodgkin) and others