The symptoms of reactive arthritis usually develop within four weeks of infection.

In most cases, reactive arthritis follows a sexually transmitted infection (STI) such as chlamydia, or a bowel infection such as food poisoning.

The three parts of the body most commonly affected by reactive arthritis are the:

• joints and tendons
• urinary system
• eyes

However, most people won’t experience problems in all of these areas.

Joints and tendons

Reactive arthritis usually involves inflammation of the joints (arthritis) and tendons, which can cause:

• joint pain, tenderness and swelling – usually in weight-bearing joints such as your knees, feet and ankles
• lower back and buttock pain
• swelling of your fingers and toes
• joint stiffness – particularly in the morning

The urinary system

Reactive arthritis can sometimes also involve inflammation of the urethra (non-gonococcal urethritis), which is the tube that carries urine out of the body. Symptoms of urethritis can include:

• pain or a burning sensation when you pee
• urinating more often than usual
• having a sudden urge to urinate
• a discharge of fluid from the penis or vagina
• blood in your urine (less commonly)

The eyes

Reactive arthritis may occasionally involve inflammation of the eyes (conjunctivitis). Symptoms of conjunctivitis can include:

• red eyes
• watery eyes
• eye pain
• swollen eyelids

In rare cases, a type of uveitis, called iritis can develop. Iritis can cause the eyes to become painful, red and sensitive to light. See your doctor or an eye specialist as soon as possible if you have these symptoms.

Other symptoms

Reactive arthritis can also cause symptoms, including:

• feeling unusually tired
• a high temperature (fever)
• weight loss
• mouth ulcers
• painless white patches inside your mouth
• a rash
• thick and crumbly nails
• abdominal (tummy) pain
• bouts of diarrhoea