In order to make a definite diagnosis of myositis, the following criteria must be met:
Patients should exhibit at least one of the following:
- Weakness of the shoulder and/or hip muscles.
- In cases of dermamyositis, particular skin findings are significant. Usually a patchy, reddish rash on the knuckles, or eyelids are indicative of dermatomyositis when coupled with other significant symptoms like muscle weakness.
- Elevated muscle enzymes
- Electromyography must be consistent with feature of an inflammatory myopathy
- Muscle biopsy demonstrates changes consistent with inflammation.
Your doctors may also recommend the following tests to determine if you have myositis: