Pink eye

Synonyms: Conjunctivitis, Red eye

Medical Specialties: Family practice, Ophthalmology, Pediatrics

Clinical Definition

Pink eye, medically known as conjunctivitis, is a common eye condition involving inflammation of the conjunctiva, or inner lining of the eyelid. Conjunctivitis may be caused by a virus, bacteria or allergens and is highly contagious. Additionally, foreign bodies in the eye can also irritate the conjunctiva, as well as air pollution, smoke, dust and chemical vapors.

In Our Own Words

Conjunctivitis, or pink eye, is one of the most common eye infections affecting both adults and children, even newborns. Bacterial and viral forms of conjunctivitis are both highly contagious. Your conjunctiva lines the inside of the eyelid and covers the white part of the eye; it contains tiny blood vessels and is usually transparent. When the tissue becomes irritated, those blood vessels become larger and make the eye appear reddish.

It can be difficult to determine exactly what causes this inflammation: An allergen, bacteria, a virus or another reason. Serious conditions that result in vision loss are ruled out first by health care professionals, and prompt treatment of bacterial conjunctivitis is highly effective and can prevent contagion.

Common Types
  • Allergic
  • Bacterial
  • Viral
Side Effects
  • Redness in the white of the eye or inner eyelid
  • Pus in the corner of the eye
  • Irritation and eye itchiness
  • Increase in tearing or mucous
Share this article
  • Centers for Disease Control and Prevention. "Conjunctivitis Causes." Conjunctivitis Oct. 2012. Accessed Aug. 2013.
  • American Academy of Ophthalmology. "Conjunctivitis: What Is Pink Eye?" Eyesmart Diseases 2013. Accessed Aug. 2013.
  • Cleveland Clinic. "Conjunctivitis." Disorders Jan. 2010. Accessed Aug. 2013.
  • CDC. "Conjunctivitis Signs & Symptoms." Conjunctivitis June 2010. Accessed Aug. 2013.
Keep Reading

Investigate your bodys signs and signals.
Try Symptom Checker