Polymyalgia rheumatica (PMR) is an essentially benign (not life-threatening) inflammatory disease characterized by pain and stiffness in the muscles in and around the neck, shoulders and hips. It may develop rapidly but usually goes away over several years, even without treatment. With treatment, symptoms typically disappear in less than a week.

PMR may occur along with temporal arteritis, a condition that causes arteries, particularly those in the head, to swell. It is not known how or why PMR and temporal arteritis are connected, but temporal arteritis can potentially be life-threatening and is typically tested for along with PMR.

The cause of PMR has not been identified, but white women over the age of 50 are most commonly affected. Theories on the possible causes of PMR include links to genetics, aging, climate and viral infections.

Muscle pain and morning stiffness are the characteristic symptoms of PMR. Other symptoms include arthritis, joint swelling, edema (swollen tissue) and flu-like symptoms (e.g., general weakness, feeling of being unwell, loss of appetite).

PMR is a clinical diagnosis, mainly a diagnosis of exclusion, meaning other conditions should be ruled out. The only blood test found positive is the sedimentation rate (sed rate). Most physicians agree that the following criteria must be met for diagnosis of PMR:

• Patient over age 50.
  
  
• Aching and stiffness on both sides of the body that lasts at least 30 minutes and persists for at least one month.
  
  
• Sed rate over 40 millimeters per hour. This blood test detects inflammation by measuring the rate at which red blood cells fall in blood plasma.

Some physicians add another requirement – that symptoms respond quickly to corticosteroids. Also, other conditions that may cause the necessary criteria (e.g., rheumatoid arthritis, fibromyalgia, polymyositis) must be ruled out.

PMR is typically treated with low-dose corticosteroids, which eliminate symptoms quickly. Once symptoms disappear, the dose is reduced to the lowest effective dose and treatment with this drug is eventually ended. However, if the dosage is reduced too quickly or treatment is ended too soon, a relapse may occur.

PMR affects less than 1 percent of the U.S. population over the age of 50, according to the National Institutes of Health.