Also known as muscle inflammation, inflammatory myositis is a rare condition that can affect people all ages. 

There are two main clusters of patients; children between the ages of 5 to 15 years and adults between the ages of 30 to 65 years.  Generally, women are twice more likely to develop myositis than men. 

This condition causes the muscle to be weak and can also result in muscle ache and swelling. There are many types of inflammatory myositis but the major types include:

Dermatomyositis 

In addition to muscle weakness, there may be a rash on the skin, especially around the eye-lids and the fingers. Cancer is found in approximately 10%-20% of cases. Sometimes, the muscle problem develops first. In other cases, the cancer is detected before the myositis.

Polymyositis  

The condition may affect the muscles alone without a rash. Cancer is not commonly associated with polymyositis, unlike in dermatomyositis.

Inclusion body myositis

The condition causes severe muscle weakness and wasting throughout the body over a long period of time.

Drug-induced myositis 

The condition is triggered by the body's response to a type of cholesterol lowering drug called statins.  The symptoms of muscle pain and weakness can manifest over a short period of time, but patients can also improve rapidly once the medication is stopped.