Reactive arthritis
Reactive arthritis, formerly known as Reiter's syndrome, is a condition that causes inflammation (redness and swelling) in various places in the body.
The symptoms of reactive arthritis usually develop within four weeks of an infection.
It's not known exactly what causes reactive arthritis, but it's thought to be the result of the immune system reacting to an infection.
There's currently no cure for reactive arthritis, but the condition is usually temporary and treatment can help to relieve your symptoms.