Rheumatoid arthritis is an inflammatory disease that affects the joints. In people with rheumatoid arthritis, the immune system produces white blood cells that attack the synovium, a lining of tissue that surrounds the joint. (See Rheumatoid Arthritis Overview.) This causes inflammation and makes the joint swollen and painful. It can cause swelling, stiffness, pain and loss of function in the joints it affects.
One of the common symptoms is referred to as Rhuematoid Arthritis Rash. Rashes can occur for many reasons in anybody. However, in people with rheumatoid arthritis, the medications or, more uncommonly, the disease itself can cause rashes. Medications that commonly cause rashes as side effects include methotrexate, leflunomide and hydroxychloroquine. A rare, and serious, complication of rheumatoid arthritis is vasculitis, an inflammation of blood vessels, which can cause rash that most commonly appears in the finger tips, toes, or legs.
A more recently FDA approved medication, etanercept, has also been linked to rheumatoid arthritis rashes. One patient with a 20 year history of rheumatoid arthritis had been previously treated unsuccessfully with nine different drugs. It was decided to start her on etanercept therapy with twice weekly injections. She tolerated the first five injections well and her rheumatoid arthritis symptoms were reducing. However, on the day she was to have received her sixth injection the doctor noted that she had developed itchy rashes at all of her previous injection sites. The rashes were treated with chlorpheniramine which cleared within 4 days. Restarting the etanercept therapy resulted in another injection site rash which was again treated and the patient continued to receive both drugs as her arthritis symptoms responded well to the etanercept.
How common is rheumatoid arthritis rash? A Japanese study in 1995 found that about 10% of 142 patients exhibited a rheumatoid arthritis rash. These were identified as rheumatoid nodules, rheumatoid papules and severe vasculitic ulcers.
Rheumatoid nodules are bumps that grow in the soft tissues and are commonly found on the elbows, but can occur anyplace on the body and feel like a hard lump. These can appear and disappear and create a problem if they are over a bony area and perforate the skin.
Rheumatoid papules are raised nodules usually on the knuckles and hands.
Vasculitis is the most concerning. This is an inflammation of the blood vessels and results in blocking the blood supply to tissues.
Small vessel vasculitis looks like red blotchy abrasions on the hands and feet can result in dead tissue under the nails, which appear as black spots. These require a physician to determine that there is no blood vessel inflammation affecting any other organs. Red patches that are accompanied by bruising also necessitates a physicians assessment because these can be the result of a larger vessel vasculitis.
Larger vessel vasculitis causes ulcers of the skin and should be treated with concern because they could indicate that other, deeper, blood vessels are also affected. Consulting a physician should be a top priority with these symptoms.
Rheumatoid arthritis rashes can be confused with psoriatic arthritis which is a form of joint inflammation in some people who have psoriasis. This type of arthritis occurs in about 7% of people with psoriasis. Psoriatic arthritis usually affects the joints of fingers and toes which may become swollen and deformed as a result of chronic inflammation.