Conjunctivitis (patient information)
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What is conjunctivitis?
Conjunctivitis (commonly called "pink eye" or "Madras eye"[1]) is an acute inflammation of the conjunctiva (the outermost layer of the eye and the inner surface of the eyelids), most commonly due to an allergic reaction or an infection (usually viral, but sometimes bacterial[2]). While this article relates generally to humans, animals such as canines (dogs) and cattle can experience this condition.
What are the symptoms of conjunctivitis?
Redness (hyperaemia), irritation (chemosis) and watering (epiphora) of the eyes are symptoms common to all forms of conjunctivitis. Other general symptoms of conjunctivitis include:
- Blurred vision
- Crusts that form on the eyelid overnight
- Eye pain
- Gritty feeling in the eyes
- Increased tearing
- Itching of the eye
- Redness in the eyes
- Sensitivity to light
Allergic conjunctivitis
Allergic conjunctivitis is typically itchy, sometimes distressingly so, and often involves some eye swelling. Chronic allergy often causes just itching or irritation.
Allergic conjunctivitis shows pale watery swelling or edema of the conjunctiva and sometimes the whole eyelid, often with a ropy, non-purulent mucoid discharge. There is variable redness.
Viral conjunctivitis Viral conjunctivitis is often associated with an infection of the upper respiratory tract, a common cold, and/or a sore throat. Its symptoms include watery discharge and variable itch. The infection usually begins with one eye, but may spread easily to the other.
Viral conjunctivitis, commonly known as "pink eye", shows a fine diffuse pinkness of the conjunctiva which is easily mistaken for the 'ciliary injection' of iritis, but there are usually corroborative signs on bio microscopy, particularly numerous lymphoid follicles on the tarsal conjunctiva, and sometimes a punctate keratitis.
Bacterial conjunctivitis Bacterial conjunctivitis due to the common pyogenic (pus-producing) bacteria causes marked grittiness/irritation and a stringy, opaque, grey or yellowish mucopurulent discharge (mucus, gowl, goop, gunk, eye crust, or other regional names, officially known as 'gound') that may cause the lids to stick together (matting), especially after sleeping. Another symptom that could be caused by bacterial conjunctivitis is severe crusting of the infected eye and the surrounding skin. However discharge is not essential to the diagnosis, contrary to popular belief. Bacteria such as Chlamydia trachomatis or Moraxella can cause a non-exudative but persistent conjunctivitis without much redness. The gritty and/or scratchy feeling is sometimes localized enough for patients to insist they must have a foreign body in the eye. The more acute pyogenic infections can be painful. Like viral conjunctivitis, it usually affects only one eye but may spread easily to the other eye. However, it is dormant in the eye for three days before the patient shows signs of symptoms.
Pyogenic bacterial conjunctivitis shows an opaque purulent discharge, a very red eye, and on bio microscopy there are numerous white cells and desquamated epithelial cells seen in the tear duct along the lid margin. The tarsal conjunctiva is a velvety red and not particularly follicular. Non-pyogenic infections can show just mild infection and be difficult to diagnose. Scarring of the tarsal conjunctiva is occasionally seen in chronic infections, especially in trachoma.
Chemical conjunctivitis Irritant or toxic conjunctivitis is irritable or painful when the infected eye is pointed far down or far up. Discharge and itch are usually absent. This is the only group in which severe pain may occur.
Irritant or toxic conjunctivitis show primarily marked redness. If due to splash injury, it is often present only in the lower conjunctival sac. With some chemicals—above all with caustic alkalis such as sodium hydroxide—there may be necrosis of the conjunctiva with a deceptively white eye due to vascular closure, followed by sloughing of the dead epithelium. This is likely to be associated with slit-lamp evidence of anterior uveitis.
Other Inclusion conjunctivitis of the newborn (ICN) is a conjunctivitis that may be caused by the bacteria Chlamydia trachomatis, and may lead to acute, purulent conjunctivitis.[3] However, it is usually self-healing.[3]
Conjunctivitis is identified by irritation and redness of the conjunctiva. Except in obvious pyogenic or toxic/chemical conjunctivitis, a slit lamp (biomicroscope) is needed to have any confidence in the diagnosis. Examination of the tarsal conjunctiva is usually more diagnostic than the bulbar conjunctiva.
What are the causes of conjunctivitis?
Conjunctivitis is most commonly caused by viruses, often adenovirus, but many other factors can lead to its occurrence. Other causes include:
- Allergies (allergic conjunctivitis)
- Bacteria
- Certain diseases
- Chemical exposure
- Chlamydia
- Fungi
- Parasites (rarely)
- Use of contact lenses (especially extended-wear lenses)
Additionally, newborns can be infected by bacteria in the birth canal. This condition is called ophthalmia neonatorum, and it must be treated immediately to preserve eyesight.
Commonly, conjunctival infections are passed from person-to-person due to lack of hygiene measures.
Who is at risk for conjunctivitis?
Additionally, newborns can contract ophthalmia neonatorum, a form of bacterial conjunctivitis, during delivery. This can occur when the baby's eyes are exposed to the bacterial in the birth canal from a mother infected with either Neisseria gonorrhoeae or Chlamydia trachomatis. It must be treated immediately to prevent blindness.
How to know you have conjunctivitis?
When to seek urgent medical care
Treatment options
Diseases with similar symptoms
Where to find medical care for conjunctivitis
Directions to Hospitals Treating conjunctivitis
Prevention of conjunctivitis
Good hygiene can help prevent the spread of conjunctivitis:
- Change pillowcases frequently.
- Do not share eye cosmetics.
- Do not share towels or handkerchiefs.
- Handle and clean contact lenses properly.
- Keep hands away from the eye.
- Replace eye cosmetics regularly.
- Wash your hands often.
What to expect (Outlook/Prognosis)
Sources
http://www.nlm.nih.gov/medlineplus/ency/article/001010.htm
- ↑ "Beware, `Madras eye' is here!". The Hindu. 2001-10-12. Retrieved 2008-10-30.
- ↑ Langley JM. Adenoviruses. Pediatr Rev. 2005;26:238-242.
- ↑ 3.0 3.1 Fisher, Bruce; Harvey, Richard P.; Champe, Pamela C. (2007). Lippincott's Illustrated Reviews: Microbiology (Lippincott's Illustrated Reviews Series). Hagerstown, MD: Lippincott Williams & Wilkins. ISBN 0-7817-8215-5.