Other forms of inflammatory arthritis

Osteoarthritis, rheumatoid arthritis and gout are the most common forms of arthritis but there are several other types that are also important, although they are much rarer. Some of these forms of arthritis develop in people with other conditions – the arthritis may form a major part of the disease or be a relatively minor problem. In these forms of arthritis, the joints are inflamed, that is, like rheumatoid arthritis, they are forms of inflammatory arthritis.

Ankylosing spondylitis

This condition causes inflammation of the joints in the spine, including the sacroiliac joints which link the spine to the pelvis, and the hips are also sometimes affected. It is three times more common in men than in women and it usually develops between the ages of 20 and 40. The risk is 10 to 20 times higher for those who have a parent, brother or sister with the condition.

Ankylosing spondylitis is closely linked with an inherited factor known as tissue type HLA-B27. Only about 8 per cent of the population have HLA-B27, but 95 per cent of ankylosing spondylitis sufferers carry this tissue type.

Symptoms of ankylosing spondylitis

The main symptom is pain and stiffness in the lower back and hips, which is much worse in the mornings when it often lasts for several hours. The spine loosens up with activity and exercise but the stiffness recurs the following morning. Without treatment, the stiffness may spread to involve the whole spine, including the neck.

A programme of daily exercises and regular review by a physiotherapist are vital to maintain the flexibility of the spine. Without regular exercise, the spine, over time, becomes curved and fixed. Drugs can ease the pain and the subjective feeling of stiffness, but they cannot take the place of exercise in maintaining movement.

Occasionally, other joints may be affected, and pain under the heel (plantar fasciitis) can be troublesome. Sufferers may occasionally develop inflammation of the eye with red, painful watering and blurred vision. This requires urgent treatment from an ophthalmologist.

There are a number of other conditions that are similar to ankylosing spondylitis. The whole group is known medically as ‘spondyloarthritis’. These other conditions are described below.

Reactive arthritis (sometimes called Reiter’s syndrome)

This develops in some people after an infection of the bowel or urogenital system. A small number of joints, usually a knee or an ankle or both, become very swollen and painful. The joints are not infected but the inflammation develops as a result of the body’s reaction to the infection – hence the term ‘reactive arthritis’. Back pain, eye inflammation and a rash on the soles of the feet can also occur.

Inflammatory bowel disease, particularly ulcerative colitis

This can occasionally cause joint inflammation, in a pattern similar to ankylosing spondylitis but also affecting large joints such as hips, knees or ankles.

Psoriatic arthritis

Psoriasis is a very common skin condition which affects about two per cent of the population. A small proportion of these – less than 10 per cent – develop inflammatory arthritis. The joint problems may develop even though the psoriasis is mild and, occasionally, they may appear before any skin changes.

On the other hand, psoriasis sufferers with severe skin disease may never have joint problems. Psoriatic arthritis is a form of spondyloarthritis but in severe cases it can be difficult to distinguish it from rheumatoid arthritis as it often affects the small joints of the hands and feet, as well as the large joints.

Symptoms of psoriatic arthritis

Unlike rheumatoid arthritis, psoriatic arthritis may occur unevenly. In other words, one hand may be affected but not the other. Eight of ten people with psoriatic arthritis will notice that psoriasis affects their nails, so that they become pitted and chalky.

Around a third of people experience lower back pain as a result of inflammation in their sacroiliac joints, something that rarely happens in rheumatoid arthritis. Mild cases are treated with exercise and anti-inflammatory drugs. For severe cases, the drug treatment is similar to that for rheumatoid arthritis.

Arthritis in children

Children may develop painful and swollen joints, usually after a viral infection or an injury, and the condition usually settles quickly. Arthritis that lasts for more than 12 weeks is unusual and may be caused by chronic inflammation. This condition is called ‘juvenile idiopathic arthritis’ (idiopathic means that we do not know the cause of the arthritis). In the UK it affects around 12,000 children of all ages. The number of joints affected varies from one individual to another. Some children develop eye inflammation and some children may be ill with a fever and a rash.

All children with arthritis need specialist care by a hospital team, working together with their parents and teachers to ensure that the child can live as normal a life as possible.

Many children grow out of the condition in a few years, but a few have persistent problems as they grow up and a small number develop an adult form of the condition.

KEY POINTS

• There are several types of inflammatory arthritis – rheumatoid arthritis is the most common

• Children and young people can develop inflammatory arthritis and they need specialist care from a hospital clinic