Part of the "What is...?" series
In a previous blog post, we talked about the two different types of arthritis - osteoarthritis and inflammatory arthropathies (a.k.a. rheumatic diseases). This post will concentrate on inflammatory arthropathies, the most common of which is rheumatoid arthritis (RA).
RA is a type of autoimmune disease - the immune system mistakenly attacks the lining of the joints, thinking it is a foreign substance. This causes the joint to become red, hot, swollen and stiff. The symptoms are particularly worse if you've been sleeping or had a period of inactivity. You can also get "flare-ups" where the symptoms become particularly severe. It often runs in families, and is more common in women and in the over 50s. It can sometimes have effects in other areas of the body, such as the eyes, heart and lungs. It's also common to get other symptoms like fatigue and poor appetite. No-one knows why the immune system starts to behave this way, and the only known risk factor is smoking.