Common causes of Conjunctivitis include:
- Virus- commonest factor
Less common causes of Conjunctivitis include:
- Chemicals/ Irritants
- Systemic diseases
- Foreign objects
The commonest virus causing conjunctivitis is Adenovirus. It is often associated with a cold or sore throat. Other viruses included in causes of Conjunctivitis include Herpes simplex, Enterovirus, Coxsackievirus can also cause this disease. It usually begins in one eye, later affecting the other and tends to spread easily between people.
Bacterial conjunctivitis is caused by infection of the eye with certain bacteria like Staphylococci, Streptococci or Haemophilus. Poor hand washing and handling infected clothes promote such types of infections. This condition affects both eyes, with redness of eye, gritty sensation and sticky discharge in them.
Allergic conjunctivitis is caused by the body's reaction to certain substances to which it is hypersensitive. Allergic causes of Conjunctivitis include pollen from trees, plants, grasses, as well as dust mites, molds, dander from animals, contact lenses and lens solutions and cosmetics. It occurs frequently among people with other allergic conditions, such as hay fever, asthma, and eczema and can occur seasonally also.
Some people are susceptible to chemicals in swimming pools or to smoke or fumes, and these can figure in the causes of Conjunctivitis by precipitating irritation, discomfort, redness and watering. Mild burns may also produce conjunctivitis while more severe burns may cause whitening of cornea. Sometimes insertion of any foreign objects causes watering and discomfort in eyes.
Causes of Conjunctivitis in newborn include:
- Blocked tear ducts
- Use of antibiotic eye drops given to mother for irritation of eye after delivery
- The commonest bacteria that cause infection in the infant's eye come from the mother's genital tract and are passed to the infant during delivery. If not treated, they can cause serious damage to the infant's eye.
Conjunctivitis due to Systemic Diseases
Sometimes, people suffering from other diseases like Rheumatoid arthritis, Gout, Crohn's disease have greater possibility of acquiring conjunctivitis.