What is reactive arthritis?
Reactive arthritis is a relatively short-lived condition causing painful joint swelling. It develops shortly after a bowel, genital tract or, less frequently, a throat infection. In most cases, it clears up completely within 6 months causing no further problems.
Who gets reactive arthritis?
Although there isn’t a family tendency to develop reactive arthritis, if you have a particular gene, HLA-B27, you may be more likely to develop the condition. This gene is carried by about 1 in 14 (7%) of the general population. Having the HLA-B27 gene could also make you more likely to have further episodes of reactive arthritis in the future.
Pain and swelling, usually in the joints of the legs (knees, ankles or toes), are often the first signs of reactive arthritis. Swelling may happen suddenly or develop over a few days after the affected joint becomes stiff.
Other joints including the fingers, wrists, elbows and the joints at the base of your spine (sacroiliac joints) can also become inflamed.
Reactive arthritis can also cause inflammation of the tendons around the joints, such as the Achilles tendon at the back of the ankle.
If both the tendons and joints of one finger or toe are affected at the same time, it can cause that finger or toe to become swollen like a sausage (dactylitis).
Joint pain and swelling are often the only symptoms of reactive arthritis. But other possible symptoms include:
- inflamed, red eyes (conjunctivitis)
- scaly rashes over your hands or feet (known as keratoderma blenorrhagica)
- diarrhoea, which may start some time before the arthritis
- mouth ulcers
- inflammation of the genital tract which produces a discharge from your vagina or penis
- a sore rash over the end of the penis
- weight loss and fever.
Unlike septic arthritis, reactive arthritis isn’t caused by an active infection within your joints. With reactive arthritis the inflammation in your joints is a reaction to an infection elsewhere in your body. Reactive arthritis is diagnosed if you suddenly develop arthritis, especially in your knees or ankles, just after suffering an infection. Sometimes the infection may have been so mild that you didn't notice it.
Reactive arthritis most commonly develops after infections of the bowel or genital tract.
It's not known exactly why this happens. One theory is that once your immune system has dealt with the original infection, fragments of bacteria may be carried through your bloodstream and deposited in the lining of your joints. This could trigger an inflammatory reaction.
Chlamydia, the most common sexually transmitted infection (STI) in the UK, can trigger bouts of reactive arthritis. It often doesn’t have any symptoms (especially in women), but it may cause pain on passing urine or discharge from your vagina or penis. If you experience these symptoms, or have had unprotected sex and are worried, see your GP or visit a sexual health clinic.
How will reactive arthritis affect me?
Reactive arthritis will usually disappear completely within 6 months. During this time you may have good days and bad days. In 10–20% of people the symptoms last longer, but only a small number of people go on to develop an ongoing arthritis that requires longer term treatment.
Some people, especially those who have the HLA-B27 gene, may have bouts of reactive arthritis which come back at intervals of months or years in response to further infections. When this happens it’s described as recurrent. If you're affected in this way you should be especially careful to avoid food poisoning and the risk of sexually transmitted infections.
Usually when reactive arthritis disappears the joints make a full recovery and there are no long-term problems as a result.
Reactive arthritis can usually be told apart from other arthritic conditions because of the link to an earlier infection. Your doctor will therefore probably ask about your recent health and sexual activity if reactive arthritis is suspected.
Doctors usually diagnose reactive arthritis on the basis of one or more of the following signs:
- you suddenly develop symptoms just after an infection – but the infection may have been so mild that you didn’t notice it, so sometimes doctors diagnose reactive arthritis even when there’s no definite history of infection
- all tests for other forms of arthritis (such as rheumatoid arthritis) are negative
- the arthritis is accompanied by symptoms very typical of reactive arthritis, such as rash over the palms or soles or red painful eyes.
What tests are there?
There’s no specific test for reactive arthritis, but the following may be used to confirm a diagnosis or rule out other causes of the symptoms:
- a stool sample, or swabs taken from your throat, penis or vagina, which can be tested for signs of inflammation or infection
- blood tests to check for levels of inflammation and sometimes to test for the HLA-B27 gene.
Blood tests can also be used to test for antibodies associated with other forms of arthritis. These antibodies include rheumatoid factor and anti-nuclear antibody.
If your eyes are sore and red you may be examined by an eye specialist (ophthalmologist) in order to check that it isn’t a serious inflammation of the eye, known as iritis. This is different from conjunctivitis (which is the most common cause of a painful red eye). Iritis is inflammation of the coloured part of the eye (the iris), whereas conjunctivitis is inflammation of the white of the eye.
Medical treatments for reactive arthritis fall into three groups:
1. Treating the infection
This usually involves:
- antibiotics (usually taken by mouth) if you're found to have a bowel or genital tract infection
- eye drops or ointment to treat conjunctivitis
- steroid eye drops to treat iritis.
2. Treating the joint pain and swelling
Joint inflammation is treated according to severity. It usually involves:
- non-steroidal anti-inflammatory drugs (NSAIDs) in mild to moderate cases
- ice packs and heat pads to relieve joint pain and swelling (wrapped in a towel to protect your skin)
- splints to rest your wrist joints or heel and shoe pads for painful feet.
3. Treating severe or ongoing arthritis
If you have more severe joint symptoms you may need:
- to have some fluid removed from the affected joint through a needle (aspiration) – steroid injection is often given into the joint at the same time
- steroid injection close to an inflamed tendon, or into a muscle (so that it spreads through the body)
- a short course of low-dose steroid tablets.
Managing your symptoms
You may find that the following help to relieve some of the symptoms.
Rest and exercise
If your joints are inflamed, you may feel tired and generally unwell. Plenty of rest and sleep can play an important role in recovery during the early stages of reactive arthritis, but it’s also important that you try to keep your joints moving and maintain muscle strength. You may be advised by a physiotherapist or occupational therapist to do particular exercises, but you should avoid putting too much strain on inflamed joints.