Complications of conjunctivitis depend on whether the condition is an infection (infective conjunctivitis) or an allergic reaction (allergic conjunctivitis).
If conjunctivitis has been caused by a sexually transmitted infection (STI), particularly chlamydia, the infection may last several months, rather than weeks.
Infective conjunctivitis caused by any type of bacteria can result in a number of complications, particularly in babies born prematurely (before week 37 of pregnancy).
Possible complications include:
- meningitis – an infection of the meninges (the protective layer of cells surrounding the brain and spinal cord)
- cellulitis – an infection of the deep layer of skin and tissue that causes the skin on the surface to become sore and inflamed. It's usually easily treated with antibiotics
- septicaemia – more commonly known as blood poisoning, septicaemia occurs when bacteria get into the bloodstream and attack the body's tissues
- otitis media – a short-term ear infection that affects around one in four children who have had infective conjunctivitis caused by the haemophilus influenzae bacteria
In newborn babies (neonates) up to 28 days old, infective conjunctivitis can lead to a severe and rapidly progressive eye infection. If this isn't treated, it can cause permanent damage to the child’s vision.
If your newborn baby is found to have infective conjunctivitis, they'll immediately be referred for specialist assessment and treatment. Their condition will be closely monitored. Complications of infective conjunctivitis are rare and most babies make a full recovery.
After having infective conjunctivitis caused by chlamydia, around one in five babies may develop pneumonia. This is a potentially life-threatening condition in young babies and may need treatment in hospital.
If your conjunctivitis is caused by an allergic reaction to pollen, dust mites or similar (seasonal and perennial allergic conjunctivitis), it's very rare to experience any serious complications.
However, you may find your reoccurring symptoms frustrating. For example, if your conjunctivitis is caused by pollen, you may find it difficult to go outside during the spring and summer months without triggering your symptoms.
This type of allergic conjunctivitis can affect your daily life and could make it difficult for you to concentrate at work or school, particularly if your eyes are severely irritated. Although this can affect your quality of life, it shouldn't cause any long-term health problems.
Read more about living with an allergy.
Punctate epithelial keratitis
Some types of conjunctivitis can cause a condition called keratitis. Keratitis is where your cornea (the front of your eye) becomes swollen.
This can be painful and make your eyes sensitive to light (photophobia). Ulcers sometimes form on the cornea. If the ulcers scar your cornea, your vision may be permanently damaged.
If you experience any unusual symptoms, contact your GP immediately or visit your nearest accident and emergency (A&E) department.