What it is HLA-B27 associated uveitis?
HLA‑B27 associated uveitis almost always affects the front of the eye (anterior uveitis or iritis) and is the most common identifiable cause of non‑infectious anterior uveitis in Western countries. It typically presents as acute, sudden‑onset, unilateral (one‑eye) inflammation that tends to recur over time.
This condition is closely linked with the HLA‑B27 gene, which is part of the immune system’s “ID tag” system on cells. HLA‑B27 uveitis is frequently associated with a group of rheumatologic diseases called spondyloarthropathies, including ankylosing spondylitis, reactive arthritis, psoriatic arthritis, and inflammatory bowel disease‑related arthritis. Although flares can be severe and complications are not rare, most patients have a good long‑term visual prognosis with timely diagnosis and treatment.
What causes it?
HLA‑B27 is a gene you are born with from your parents. Having this gene does not mean you will get eye disease, but it makes it more likely.HLA-B27 makes it more likely you could have certain types of arthritis in your spine or other joints. In many studies, HLA‑B27 accounts for about 18–32% of all anterior uveitis cases and up to roughly half of acute anterior uveitis.
Doctors are not completely sure why this gene causes eye swelling. They think the immune system may get confused and start to attack healthy eye tissue by mistake. Sometimes an infection or a flare of arthritis in the body can trigger an eye attack, and sometimes it seems to happen for no clear reason. This eye problem is more common in young and middle‑aged adults (20s-40s) and happens a bit more often in men.
What are the signs and symptoms?
HLA‑B27 associated acute anterior uveitis usually comes on suddenly, often over hours to a day or two, with noticeable symptoms. Typical symptoms include:
- Eye pain, often aching or throbbing, sometimes worse with focusing.
- Redness of the eye, especially around the cornea.
- Light sensitivity (photophobia, it hurts to look at your phone and screens), sometimes very intense.
- Blurred or decreased vision during a flare.
- Excess tearing and a small or irregularly shaped pupil.
When an eye doctor looks closely, they can see signs of inflammation inside the front of the eye. They may see tiny white blood cells and protein floating in the eye fluid, and small spots on the back of the clear front window (the cornea). Sometimes the colored part of the eye sticks to the lens behind it. In more severe cases, doctors can see clumps of cells or even a layer of white cells at the bottom of the eye. Usually only one eye is affected at a time, but attacks can switch from one eye to the other. Each attack often lasts a few weeks to a couple of months with treatment, but they can come back again. If the swelling is strong or happens many times, it can also affect the back parts of the eye and raise the chance of problems like cataracts (cloudy lens), glaucoma (high eye pressure), or swelling in the center of vision. HLA‑B27 uveitis tends to have more severe inflammation than other types of anterior uveitis. Episodes are typically unilateral but may alternate between eyes over time, and they usually resolve within a few weeks to two months, with a tendency to recur.
Although anterior uveitis predominates, a minority of patients can have involvement of the vitreous or retina (posterior uveitis), which is increasingly recognized and may increase the risk of complications. Potential complications of recurrent or poorly controlled inflammation include cataract, glaucoma, cystoid macular edema (Retinal swelling), band keratopathy (Corneal scarring), and chronic hypotony (Low eye pressure), all of which can threaten vision if not managed promptly.
Because of the strong systemic association, many patients also have or develop back pain, stiffness, enthesitis (tendon insertions), or peripheral arthritis, and uveitis can be the first presenting sign of an underlying spondyloarthropathy.
How it is treated?
The main goal of treatment is to calm down the eye swelling quickly and protect vision. Treatment also aims to prevent problems and to treat any related arthritis or other body disease. Eye doctors and rheumatologists (Joint and arthritis doctors) often work together to care for the same patient.
Main treatment components:
- Steroid eye drops to reduce swelling in the front of the eye. These are often used many times a day at first and then slowly decreased over weeks.
- Dilating drops to make the pupil big. These drops help with pain and keep the colored part of the eye from sticking to the lens leading to scar formation (Synechiae).
- Stronger steroids by mouth or by injection around the eye if the swelling is severe, in both eyes, or affecting the back of the eye.
- Medicine that calms the immune system, such as methotrexate or other similar drugs, if attacks happen often or last a long time. These medicines can help reduce the need for long‑term steroids.
- Special medicines called biologics, such as adalimumab (anti‑TNF drugs), may be used when other treatments do not work well enough or cause too many side effects.
Regular checkups are very important. The doctor will check eye pressure, the lens, and the back of the eye to look for early signs of trouble. Complications and vision loss are more frequent in patients with chronic or recurrent inflammation, especially in older individuals or those with retinal involvement (Posterior uveitis). With good care and follow‑up, most people keep good eyesight even if they have repeated flares.
What is the prognosis?
Most people with HLA‑B27 uveitis do well over time, especially if they get treatment early when a flare starts. Many attacks get better over a few weeks, and vision can return to normal or close to normal between flares. However, the condition is typically recurrent, with many patients experiencing multiple flares over their lifetime, often alternating between eyes. The risk of permanent visual impairment increases when inflammation is frequent, severe, or inadequately controlled, or when there is intermediate or posterior segment involvement.
Complications due to uveitis such as cataract formation, glaucoma, cystoid macular edema, and band keratopathy become more likely with repeated or chronic inflammation and with prolonged steroid use. Close, regular follow‑up with an ophthalmologist allows early detection and management of these problems, which greatly improves visual outcomes. People who also treat their arthritis or other body disease and take their medicines as directed often have fewer and milder flares. Even though this condition can be lifelong and can come and go, many people are able to live normal lives and keep good vision with the right care.
It’s important to see a uveitis specialist (Like me!) to control inflammation early and aggressively, and use advanced treatments to get better long-term results and reduce the chance of permanent vision loss from uveitis.
