Reaching an accurate diagnosis is often a long and frustrating process for myositis patients and their doctors. Because myositis is a rare disease, many people are misdiagnosed for years, or remain undiagnosed, without a name or explanation for their condition.

The following diagnostic criteria may be used as a guide to establish a specific diagnosis.

• Inclusion body myositis
• Juvenile Dermatomyositis
• Polymyositis/Dermatomyositis