Some physicians believe that there are different types of Fibromyalgia (FM), and some think that there is only one main form of FM, also known as primary FM, which is responsible for the wide variety of symptoms in FMS patients.

Primary FM

Primary FM is the most universally accepted form of FM, and is normally diagnosed when no other underlying rheumatologic disease, such as:

• arthritis or lupus is present, and
• at least 11 of 18 designated tender points are confirmed.

Other types of FM that have been identified include concomitant FM, which occurs with along with seemingly unrelated conditions such as osteoarthritis or scoliosis; and secondary or reactive FM, which is thought to occur as a result of the onset of another known disease or injury.

Secondary FM

Secondary FM may be triggered by conditions such as:

• rheumatoid arthritis
• lupus
• hypothyroidism
• HIV
• cancer

It may also be triggered my physical trauma such as:

• suffered after a car accident
• suffered in a work injury

Secondary FM is sometimes referred to as post-traumatic FM, and some physicians think that this particular form of FM may remain confined to the injury site. This "regional FM" may be present in patients who experience pain at fewer than 11 of 18 positive tender points.