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Symptoms
Redness, irritation and watering of the eyes are symptoms common to all forms of conjunctivitis. Itch is variable.
Acute allergic conjunctivitis is typically itchy, sometimes distressingly so, and the patient often complains of some lid swelling. Chronic allergy often causes just itch or irritation, and often much frustration because the absence of redness or discharge can lead to accusations of hypochondria.
Viral conjunctivitis is often associated with an infection of the upper respiratory tract, a common cold, 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 fellow eye.
Bacterial conjunctivitis due to the common pyogenic (pus-producing) bacteria causes marked grittiness/irritation and a stringy, opaque, grey or yellowish mucopurulent discharge (gowl, goop, sleep, or other regional names) that may cause the lids to stick together (matting), especially after sleeping. However discharge is not essential to the diagnosis, contrary to popular belief. Many other bacteria (e.g., Chlamydia, Moraxella) can cause a non-exudative but very persistent conjunctivitis without much redness. The gritty and/or scratchy feeling is sometimes localised 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.
Irritant or toxic conjunctivitis is irritable or painful. Discharge and itch are usually absent. This is the only group in which severe pain may occur.
Signs
Infection (redness) of the conjunctiva on one or both eyes should be apparent, but may be quite mild. 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.
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, commonly known as "pink eye", shows a fine diffuse pinkness of the conjunctiva which is easily mistaken for the 'ciliary infection' of iritis, but there are usually corroborative signs on biomicroscopy, particularly numerous lymphoid follicles on the tarsal conjunctiva, and sometimes a punctate keratitis.
Pyogenic bacterial conjunctivitis shows an opaque purulent discharge, a very red eye, and on biomicroscopy there are numerous white cells and desquamated epithelial cells seen in the 'tear gutter' along the lid margin. The tarsal conjunctiva is a velvety red and not particularly follicular. Non-pyogenic infections can show just mild injection and be difficult to diagnose. Scarring of the tarsal conjunctiva is occasionally seen in chronic infections, especially in trachoma.
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.
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Important notice:
The content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other
qualified health provider with any questions you may have regarding a medical condition.
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