Polymyositis and psoriatic arthritis: a quick guide

There are over 100 different types of arthritis. Don't use nutshell descriptions as a way of diagnosing your aches and pains. Make an appointment with your doctor and undergo a thorough physical. Your symptoms are unique and only your doctor can determine which disease you may have.

Finding the appropriate specialist or specialists is an important part of diagnosing your symptoms. It may take time to rule out the many other disorders that mimic your particular manifestation of arthritis before your doctor can make a final diagnosis. Once again, you and your doctor should be the architects of this important diagnosis process.

To help give you an idea of what polymyositis and psoriatic arthritis are all about, here's a quick guide. You can use this information to start a conversation with your doctor.

Polymyositis is a chronic connective tissue disease. Painful inflammation and degeneration of the muscles characterize this disease. It's a condition that occurs in adults from ages 40 to 60 or in children ages 5 to 15 years. Women are twice as likely as men to develop this condition.

Causes and symptoms

Although the cause is unknown, viruses or autoimmune reactions may play a role in causing polymyositis. Cancer may also trigger the disease.

Symptoms, which may begin during or just after an infection, include muscle weakness (particularly in the upper arms, hips and thighs), pain in your muscles and joints, a rash, difficulty in swallowing, a fever, fatigue or weight loss.

Polymyositis is often diagnosed based on measuring muscle weakness at the shoulders or hips, or detecting a characteristic rash or increased levels of certain muscle enzymes in your blood.

What can be done

Restricting activities when the inflammation is most intense often helps with cases of polymyositis.

Generally, an oral corticosteroid (usually prednisone) slowly improves strength and relieves pain and swelling, controlling the disease. In some cases, though, prednisone actually worsens the disease. In these cases, immunosuppressive drugs are used instead of, or alongside, prednisone.

Psoriatic arthritis resembles rheu­matoid arthritis, but doesn't produce the antibodies characteristic of rheumatoid arthritis. One negative rheumatoid factor test helps distinguish psoriatic arthritis from rheumatoid arthritis.

Psoriatic arthritis affects about ten percent of people who have the skin disease psoriasis. This sort of arthritis may develop at any age, but typically between the ages of 30 and 50, with heredity appearing to play a significant role in susceptibility.

Causes and symptoms

Psoriasis (a skin condition causing flare-ups of red, scaly rashes and thickened, pitted nails) may precede or follow the joint inflammation.

Psoriatic arthritis usually affects joints of the fingers and toes. The joints may become swollen and deformed when inflammation is chronic.

What can be done

Treatment of psoriatic arthritis is aimed at controlling the skin rash and alleviating the joint inflammation. Several drugs that are effective in treating rheumatoid arthritis are also used to treat psoriatic arthritis. These include gold compounds, methotrexate, cyclosporine and sulfasalazine.

If you're concerned about arthritis, keep this information in mind before your next doctor's visit so that you can talk to your doctor about it and work toward a solution.