Episcleritis: symptoms, causes and treatment

Patient.info says episcleritis tends to come on quickly. It causes redness, often in a wedge shape over the white of the eye, and mild discomfort. The eyes may water a little and the eye may be a little tender when pressure is applied over the red area. Vision is unaffected and painkillers are not generally needed.

Moorfields says it often causes irritation, soreness or a gritty sensation, and that it can affect one or both eyes. Patient.info describes two types: diffuse episcleritis, where the eye surface is evenly red, which is the most common, and nodular episcleritis, which comes on more slowly and causes inflamed swollen bumps in the episclera.

A red eye should not be assumed to be episcleritis. The NHS says to ask for an urgent appointment with a GP or optician, or get help from NHS 111, if your eye is very painful and red, or you wear contact lenses and have a red eye.

The NHS says to call 999 or go to A&E if you have a red eye and any changes to your sight, such as wavy lines, flashing or loss of vision, it hurts to look at light, you have a severe headache and feel sick, your eye is very dark red, you have injured your eye, or one pupil is bigger than the other. Do not drive to A&E.

NICE Clinical Knowledge Summaries lists red flag features of a serious or sight-threatening cause: reduced visual acuity, moderate to severe pain, headache, photophobia, unequal or misshapen pupils and a corneal defect. Patient.info says that if episcleritis does not settle over a week, or pain becomes worse and vision is affected, you should see a doctor in case you have scleritis.

Patient.info says episcleritis does not necessarily need any treatment, and if symptoms are mild it generally settles by itself. Lubricating eye drops or ointment may ease the discomfort whilst symptoms settle. If the eye is very uncomfortable, it may be treated with non-steroidal anti-inflammatory (NSAID) eye drops. If this is not enough, which is more likely in the nodular type, steroid eye drops are sometimes used, but only under the care of an ophthalmologist.

The NHS general advice for a red eye that does not hurt, has no effect on sight and does not make you feel unwell is to try not to touch or rub your eye and not to wear contact lenses until it has got better, and that a pharmacist can advise on cleaning solutions and eye drops.

Moorfields says the cause of episcleritis is mostly unknown. It sometimes flares up when you are tired, have been reading or working on computers for long periods, or are in a dry, dusty environment. Very rarely, it may be due to an underlying inflammation in the body, which can be investigated by blood tests if the episcleritis is severe and recurrent.

Patient.info says it is not known what triggers the inflammation, which seems to start in the small blood vessels on the surface of the eye. It is most common in adults in their 40s and 50s, slightly more common in women, and in people with connective tissue disease such as rheumatoid arthritis. About 40 people per 100,000 per year are thought to be affected.

Moorfields explains that the episclera is the layer of tissue between the conjunctiva (the surface membrane) and the sclera (the firm white part of the eye). In episcleritis the episclera becomes inflamed and red. Patient.info says it is generally a mild condition with no serious consequences, and that many people have it and never see a doctor.

Patient.info says most attacks last 7 to 10 days, although nodular episcleritis can be a little longer, and that it is often recurrent with episodes typically every few months. It says episcleritis does not usually lead to complications, and does not usually have significant long-term consequences unless it is associated with an underlying disease such as rheumatoid arthritis.

Moorfields and Patient.info describe episcleritis as inflammation of the episclera, with a mostly unknown cause, rather than as an infection. By contrast, the NHS says conjunctivitis that produces sticky pus is contagious. If you have a red eye with a sticky discharge, the NHS says to see a GP or optician.

Patient.info says episcleritis and scleritis can look similar at first but do not feel similar and do not behave similarly. Episcleritis does not cause scleritis, although scleritis can lead to associated episcleritis.

The NHS says a pharmacist can advise on a mild red eye, and to see a GP or optician if you have red patches in your eye or a problem with eyelids or lashes for more than a few days. If they cannot find the cause, they may refer you to an eye specialist. Patient.info says scleritis needs urgent referral to an ophthalmologist, usually the same day.

Some people go directly to a private optometrist or ophthalmologist. The tests and treatments are the same, and recurrent or severe episcleritis may lead to blood tests to look for an underlying condition.