Conjunctivitis

Conjunctivitis is a common condition that causes redness and inflammation of the thin layer of tissue that covers the front of the eye (the conjunctiva).

People often refer to conjunctivitis as red eye.

Other symptoms of conjunctivitis include itchiness and watering of the eyes, and sometimes a sticky coating on the eyelashes (if it's caused by an allergy). Read more about the symptoms of conjunctivitis.

Conjunctivitis can affect one eye at first, but usually affects both eyes after a few hours.

What causes conjunctivitis?

The conjunctiva can become inflamed as result of:

• a bacterial or viral infection - this is known as infective conjunctivitis
• an allergic reaction to a substance such as pollen or dust mites - this is known as allergic conjunctivitis
• the eye coming into contact with substances that can irritate the conjunctiva, such as chlorinated water or shampoo, or a loose eyelash rubbing against the eye - this is known as irritant conjunctivitis

Read more about the causes of conjunctivitis.

Treating conjunctivitis

Conjunctivitis often doesn't require treatment as the symptoms usually clear up within a couple of weeks. If treatment is necessary, the type of treatment will depend on the cause. In severe cases, antibiotic eye drops can be used to clear the infection.

Irritant conjunctivitis will clear up as soon as whatever is causing it is removed.

Allergic conjunctivitis can usually be treated with anti-allergy medications such as antihistamines. If possible, avoid the substance that triggered the allergy.

It's best not to wear contact lenses until the symptoms have cleared up. Any sticky or crusty coating on the eyelids or lashes can be cleansed with cotton wool and water.

Washing your hands regularly and avoiding sharing pillows or towels will help prevent it spreading.

Read more about treating conjunctivitis.

See your GP immediately if you have:

• eye pain
• sensitivity to light (photophobia)
• disturbed vision
• intense redness in one or both of your eyes
• a newborn baby with conjunctivitis 

Work and school

Public Health England advises that you do not need to stay away from work or school if you or your child has conjunctivitis, unless you are feeling particularly unwell.

If there are a number of cases of conjunctivitis at one school or nursery, you may be advised to keep your child away from the school until their infection has cleared up.

Generally, adults who work in close contact with others, or share equipment such as phones and computers, should not return to work until the discharge has cleared up.

Complications

Conjunctivitis can be a frustrating condition - especially allergic conjunctivitis - but in most cases it doesn't pose a serious threat to health.

Complications of conjunctivitis are rare but when they do occur they can be serious and include:

• a severe case of allergic conjunctivitis can lead to scarring in the eye
• in cases of infective conjunctivitis, the infection can spread to other areas of the body, triggering more serious secondary infections such as meningitis (an infection of the outer layer of the brain)

Read more about the complications of conjunctivitis.