DEAR DOCTOR: I was just diagnosed with erosive osteoarthritis. What can you tell me about it? I have it mainly in my hands and feet.
DEAR DOCTOR: First, let's explain the most common form of arthritis, known simply as osteoarthritis, which develops slowly over time due to complex changes in cartilage, bone and joint linings. Formerly known as "wear and tear" arthritis, osteoarthritis has no inflammatory component and typically occurs in multiple joints throughout the body. Erosive osteoarthritis, on the other hand, is an inflammatory form of the disease that occurs primarily in the hands and, sometimes, in the feet.
In the hands, erosive osteoarthritis develops earlier in life than does typical osteoarthritis, usually between the ages of 40 and 50. It's most commonly diagnosed in women (rarely men) at the time of menopause, suggesting that loss of estrogen is a factor.
Unlike typical osteoarthritis, erosive osteoarthritis has a sudden and aggressive onset. The hand joints become warm, red, swollen and tender, making it difficult to move the fingers. With this degree of inflammation, the disease can look much like rheumatoid arthritis, but unlike rheumatoid arthritis, erosive osteoarthritis involves the joints at the end of the fingers. Bony swellings develop upon these joints, creating what appears to be nodules. The joints lose their structure so much that the finger bones move laterally in opposite directions, making the fingers look wavy instead of straight.
The inflammation can cause cartilage and bone in the joint to erode, giving the disease its name. In severe cases, the joints fuse, making movement almost impossible. The inflammatory course of the disease can last for months or come and go for up to five years. However, even when the inflammation subsides, the damage leads to long-term deformities and loss of function of the involved joints.
There are no specific lab tests to diagnose erosive osteoarthritis. Your doctor may have done blood tests to rule out diseases such as rheumatoid arthritis, but the symptoms in your hands and feet were his or her greatest clue. Patients may have some elevated inflammatory markers, but the disease is primarily diagnosed by a person's symptoms. X-rays of the hands can show specific erosions in the bones that are unique to the disease.
Decreasing inflammation is the first place to start. This can be done with topical anti-inflammatories such as diclofenac or oral anti-inflammatories such as ibuprofen, naproxen, meloxicam or celecoxib. Drugs used for rheumatoid arthritis can also ease the inflammation and erosion of erosive osteoarthritis. These include hydroxychloroquine, methotrexate and the injectable drug Humira. For severe cases, injecting steroids directly into the finger joints can decrease deformities. Also, though the data are limited, one study showed a decrease in erosions and improvement of symptoms among people taking 800 milligrams of the supplement chondroitin in addition to Naprosyn (naproxen).
Physical therapy can also improve finger mobility and reduce the likelihood that the fingers will become excessively crooked.
My advice is to treat the disease early. Although the inflammatory portion of erosive osteoarthritis is relatively short, controlling the inflammation with medication and getting hand therapy will reduce the likelihood of the deformities that can happen with the disease.
(Robert Ashley, M.D., is an internist and assistant professor of medicine at the University of California, Los Angeles.)