Reactive arthritis

Overview

Reactive arthritis is a condition that causes pain and swelling in your joints. It usually starts after you have had an infection somewhere else in your body, such as in your digestive system or urinary tract. Your immune system reacts to the infection and mistakenly attacks your joints, eyes, and sometimes your skin or urinary system. It is not contagious and often gets better on its own within a few months.

Reactive arthritis is not very common. It occurs in a small number of people who have certain infections, such as food poisoning or sexually transmitted infections.

It can affect people of any age, but it is most common in young adults between 20 and 40 years old. Men are more likely to develop it after a sexually transmitted infection, while women and men are equally at risk after a gut infection.

Symptoms

Common symptoms

• Pain, swelling, and stiffness in the joints, especially in the knees, ankles, and feet.
• Redness, pain, or irritation in the eyes (conjunctivitis or uveitis).
• Burning or pain when urinating, or a frequent need to urinate.

Symptoms in children

• Joint pain and swelling that can affect multiple joints at once.
• Fever and feeling generally unwell.
• Skin rashes or small sores on the palms of the hands or soles of the feet.

Symptoms in older adults

• Pain and stiffness in the lower back or large joints that might be mistaken for other types of arthritis.
• Symptoms may be less noticeable and take longer to develop.
• Increased risk of long-term joint problems if not treated.

Causes

Main causes

• A bacterial infection elsewhere in the body, such as a gut infection from food poisoning (e.g., Salmonella, Campylobacter) or a sexually transmitted infection (e.g., Chlamydia).
• The immune system mistakenly attacks healthy joint tissue, eyes, and other areas after the infection has cleared.

Risk factors

• Having a gene called HLA-B27, which increases your risk after certain infections.
• Being a young adult between 20 and 40 years old.
• Having a recent infection in your gut or urinary tract.

When to see a doctor

See a doctor urgently if:

• If you have severe eye pain, sudden vision changes, or extreme redness in your eye.
• If you have a high fever along with joint pain and swelling.
• If you cannot pass urine or have blood in your urine.

Book a routine appointment if:

• If you have joint pain, swelling, or stiffness that does not improve within a few days.
• If you notice redness or irritation in your eyes that lasts more than a day.
• If you have burning or pain when urinating, especially after a recent infection.

Diagnosis

A doctor will ask about your symptoms, recent infections, and medical history. They will perform a physical exam to check your joints, eyes, and skin. There is no single test for reactive arthritis, so diagnosis is based on the pattern of your symptoms and test results.

Tests that may be done

• Blood tests to look for signs of inflammation and to check for the HLA-B27 gene.
• Urine tests to check for a current infection.
• Joint fluid analysis – a small sample of fluid is taken from a swollen joint to rule out other causes.
• X-rays or ultrasound of affected joints to see if there is damage.

What to expect at your appointment

The process may take some time because symptoms can appear after an infection has cleared. You may be referred to a rheumatologist (a joint specialist) and possibly an eye doctor. Most people get a clear diagnosis within a few visits.

Treatment

Treatment aims to relieve your symptoms and help your body recover. Most people improve without long-term treatment. If the triggering infection is still present, antibiotics may be prescribed. For joint and eye symptoms, doctors focus on reducing inflammation and pain.

Self-care at home

• Rest the painful joints, but try gentle movement to keep them flexible.
• Apply ice packs to swollen joints for 15–20 minutes several times a day.
• Use heat packs or warm baths to relax stiff muscles and joints.
• Do low-impact exercises like swimming or walking as you feel able.

Medical treatments

Doctors may prescribe non-steroidal anti-inflammatory drugs (NSAIDs) to reduce pain and swelling. For more stubborn joint inflammation, they might give corticosteroid injections directly into the joint. In severe or long-lasting cases, disease-modifying antirheumatic drugs (DMARDs) or biologic medications may be used to calm the immune system. Always take medicines as prescribed and discuss any side effects with your doctor.

When is surgery considered?

Surgery is rarely needed for reactive arthritis. It may be considered only if a joint becomes severely damaged and other treatments have not worked.

Living with this condition

During flare-ups, you may need to take it easy and rest your joints. As you feel better, slowly return to your usual activities. Keep a diary of your symptoms to share with your doctor. Managing pain and fatigue is a key part of daily life.

Lifestyle tips

• Maintain a healthy weight to reduce stress on your joints.
• Practice safe sex to lower the risk of sexually transmitted infections that can trigger reactive arthritis.
• Avoid known triggers, such as certain foods that upset your stomach if you have had gut infections.

Diet and exercise

Eat a balanced diet with plenty of fruits, vegetables, whole grains, and healthy fats – these may help reduce inflammation. Gentle exercise like yoga, tai chi, or swimming can keep your joints moving without causing too much stress. Talk to a physiotherapist for a personalised plan.

Mental health and emotional wellbeing

Living with a painful condition can be frustrating and affect your mood. It is normal to feel anxious or down. Talking to a counsellor or joining a support group can help. Your doctor can also suggest ways to manage stress and improve your emotional well-being.

Prevention

You cannot always prevent reactive arthritis because it depends on your body's reaction to an infection. However, you can reduce your risk by treating infections promptly, practising safe sex, and practising good hygiene to avoid food poisoning.

Complications

If left untreated

• Chronic joint pain and damage that may last for years.
• Persistent eye inflammation (uveitis) that can affect your vision if not treated.
• Skin rashes or nail changes that may become painful.

Long-term outlook

The outlook is generally good. Most people recover fully within 3 to 12 months. Some may have symptoms that come and go, or a small number may develop long-term arthritis. With proper treatment and self-care, most people can lead active, normal lives.

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