Immune system problems
Uveitis often happens in people who have an autoimmune condition. This is where the immune system mistakenly attacks healthy tissue.
Autoimmune conditions known to cause uveitis include:
- ankylosing spondylitis – a condition where the spine and other areas of the body become inflamed
- reactive arthritis – a condition that causes inflammation in various areas of the body
- conditions that cause bowel inflammation – such as Crohn's disease and ulcerative colitis
- psoriasis – a skin condition
- psoriatic arthritis – a type of arthritis that develops in some people with psoriasis
- multiple sclerosis – a condition mainly affecting the nerves
- Behçet's disease – a rare condition that causes mouth ulcers and genital ulcers
- sarcoidosis – a rare inflammatory condition that affects the lungs, skin and eyes
- juvenile idiopathic arthritis– a type of arthritis that affects children
Uveitis can also be caused by an infection, such as:
- toxoplasmosis – an infection caused by a parasite
- herpes simplex virus – the virus responsible for cold sores
- varicella-zoster virus – the virus that causes chickenpox and shingles
- cytomegalovirus – a common infection that does not usually cause any noticeable symptoms, but can cause sight-threatening uveitis in people with a lowered immune system
- HIV and syphilis are rare causes
Uveitis can also be caused by:
- trauma or injury to the eyes, or eye surgery
- some types of cancers, such as Non-Hodgkin lymphoma, although this is a very rare cause of uveitis
Sometimes, a specific cause of uveitis cannot be identified.
Although uveitis is not passed down through families, a gene known as HLA-B27 has been linked to an increased risk of developing uveitis at the front of the eye (anterior uveitis).
About half of all people with anterior uveitis have the HLA-B27 gene. The gene has been found in people with certain autoimmune conditions, including ankylosing spondylitis and ulcerative colitis.