What causes conjunctivitis?
- Infection is most common cause
- Allergy is also a common cause, as many people with hay fever have red and inflamed conjunctiva
- Irritant conjunctivitis, which is where the conjunctiva becomes inflamed after shampoo or chlorine gets in your eyes
Common infective conjunctivitis
Most cases of infective conjunctivitis are caused by common bacteria and viruses. Often the same ones that cause coughs and colds. In the vast majority of cases, infective conjunctivitis is not serious and clears within a week or so without leaving any permanent damage to the eye.
More serious types of infective conjunctivitis
- Conjunctivitis may develop in addition to keratitis (an infection of the cornea). This is most commonly due to an infection with the herpes virus (the cold sore virus). If you have keratitis you are likely to get eye pain rather than just surface irritation, and often blurring of vision.
- A virus called adenovirus can sometimes cause a serious and prolonged conjunctivitis.
- Conjunctivitis in newborn babies can be caused by germs called chlamydia or gonorrhoea. These are serious sexually transmitted infections and need urgent treatment if they affect the eye of babies. (If a mother has one of these infections in her vagina, they can be passed on to the eye of their baby during childbirth.) Note: this is different to the very common sticky eye of newborn babies caused by a blocked tear duct. A blocked tear duct with sticky eye does not cause redness and inflammation of the conjunctiva.
- Some adults develop conjunctivitis due to chlamydia.
- When conjunctivitis is just part of a more serious infection of deeper structures of the eye, which may be indicated by eye pain, reduced vision, or swelling around the eye.
- One eye may be infected, but it usually spreads to both eyes.
- The whites of the eyes look inflamed, and red or pink.
- The eyes may feel gritty and may water more than usual.
- Some mild soreness may develop, but it is not usually very painful.
- The eyelids may become swollen, and are often stuck together with gluey material (discharge) after a sleep.
- Vision is not normally affected.
- You may get some blurring of vision due to discharge at the front of the eye. However, this clears with blinking.
- Not treating is a common option for mild or moderate infections. The tears contain chemicals that fight off bacteria. Without treatment, most cases of infective conjunctivitis clear on their own within 1-2 weeks, and often within 2-5 days. If symptoms get worse then see a doctor to check your eye and to see if you need treatment.
- Bathing the eyes with cool clean water may be soothing.
- Lubricant eye drops may reduce eye discomfort. These are available over the counter, as well as on prescription.
- An antibiotic eye drop or ointment may be prescribed in some cases. This tends to be for more severe cases, or for those that do not clear on their own.
- Do not wear contact lenses until symptoms have completely gone, and for 24 hours after the last dose of any eye drops or ointment.
- You can clean secretions from eyelids and lashes with cotton wool soaked in water.
- Infective conjunctivitis is contagious. The likelihood of passing it on is not high unless you are in close contact with others. However, until the infection has gone, to help to prevent passing it on: Wash your hands regularly, particularly after touching your eyes. Do not share towels, pillows or utensils.
Causes include the following:
- Seasonal Conjunctivitis due to pollens and moulds – symptoms will occur at the same time each year. Most cases are due to pollen and occur in the hay fever season. Symptoms tend to last a few weeks each year. Grass pollens tend to cause symptoms in early summer. Various other pollens and moulds may cause symptoms later in the summer. Other symptoms of hay fever may also occur at the same time, such as a runny nose and sore throat.
- Perennial Conjunctivitis – which persists throughout the year. This is commonly due to an allergy to house dust mite. House dust mite is a tiny insect-like creature that lives in every home. It mainly lives in bedrooms and mattresses, as part of the dust. People with perennial conjunctivitis usually also have perennial allergic rhinitis which causes symptoms such as sneezing and a runny nose. Symptoms tend to be worse each morning when you wake up.
- Animal Allergies
- Giant Papillary Conjunctivitis – is rare. It is inflammation of the conjunctiva lining the upper eyelid. It occurs in some people who have a small object on the eye – most commonly, a contact lens. It affects about 1 in 100 wearers of contact lenses. The exact cause of the inflammation is unclear – it is possibly an allergic reaction to debris caught behind a lens or to poor lens hygiene. It also sometimes develops after eye surgery.
- Contact Conjunctivitis – some people become sensitised to cosmetics, make-up, eye drops or other chemicals that come into contact with the conjunctiva. This then causes an allergic response and symptoms of conjunctivitis. In this condition the skin on the eyelids may also become inflamed. It is then called contact dermatoconjunctivitis.
- Both eyes are usually affected and symptoms tend to develop quickly.
- The eyes are usually itchy, and the whites of the eyes look red or pink.
- A burning feeling may occur, but the eyes are not usually painful.
- The eyelids tend to swell.
- The eyes water more than usual, but do not become too gluey as in infective conjunctivitis.
- Vision is not affected.
- In severe cases the conjunctiva under the upper eyelids may swell and look lumpy.
The following can be useful whatever the cause of the allergic conjunctivitis:
- If you use contact lenses: in general, do not wear lenses until symptoms have gone, and for 24 hours after the last dose of any eye drop or ointment. However, your doctor or optometrist will advise if you can wear lenses with certain types of drops.
- Try not to rub your eyes as this can cause more inflammation.
- Bathing the eyes with a flannel soaked in cold water may ease symptoms.
- Avoid the cause of the allergy, if possible. For example, if you have seasonal conjunctivitis, then during the hay fever season try staying indoors as much as possible, closing windows, wearing wrap-around sunglasses when out, etc.
Treatment For Seasonal, Perennial & Animal-Related Conjunctivitis
In addition to the general measures described above:
- No other treatment may be needed if symptoms are mild.
- Eye drops that reduce the allergic reaction are often prescribed. Two main classes of eye drops are used – antihistamine eye drops and mast cell stabiliser eye drops. (Mast cells and histamine are both involved in the allergic reaction. The eye drops counter the actions of histamine or mast cell destabilisation which results in histamine release.) There are various types and brands in each class of eye drops. The eye drops usually work well. You need to use the drops regularly to keep symptoms away until the cause of the allergy goes. Some people find one product works better than another. Therefore, if the first does not work so well, a switch to another may help. If your eyelids are very swollen, it may take several days for the drops to ease symptoms fully.
- Antihistamine tablets. You can take these to ease the general symptoms of hay fever. They may ease eye symptoms but they tend not to work as well as eye drops to ease the eye symptoms. Side-effects (mainly drowsiness) are a problem for some people who take antihistamine tablets.
- Steroid eye drops are rarely needed or used. Steroids are good at reducing inflammation. However, they should only be used if other treatments fail. They are normally only used under the supervision of an eye specialist, as infection and other causes of conjunctivitis need to be definitely ruled out. (Steroids can make some other eye conditions worse.)
- Steroid tablets are occasionally used for 3-5 days when symptoms are severe. They work well but regular or longer courses are not advised due to the problem of possible side-effects with long-term use.
A problem with contact lenses is the main cause of this. Treatment is mainly to remove contact lenses until the symptoms clear. Improved lens hygiene or a change in lens type may be advised once the symptoms have settled. Antihistamine eye drops or mast cell stabiliser eye drops (described above) may also help to ease symptoms.
Treatment For Contact Conjunctivitis
Treatment is to avoid whatever caused the reaction. When caused by a cosmetic, you should let symptoms go completely before trying an alternative product. Some cases are caused by an allergy to a particular eye drop used for another eye disease. In this situation you may need a specialist’s advice as to what alternative eye drops may be suitable for the condition. The general measures described earlier may help to soothe the eye until symptoms resolve. Antihistamine eye drops or mast cell stabiliser eye drops (described above) do not work in this type of conjunctivitis.
Our Appointments Team have a dedicated and caring approach to finding you the earliest appointment possible with the best specialist.
If you do not have a GP, then we have an in-house private GP practice that you can use. Alternatively we can suggest the most appropriate course of action for you to take, given your location and individual circumstance.
If you have medical insurance (e.g. Bupa, Axa PPP, Norwich Union), you will need to contact your insurer to get authorisation for any treatment and, in most cases, you will require a referral letter from your GP.