Last reviewed: 5 Nov 2021
Last updated: 18 Aug 2021



History and exam

Key diagnostic factors

  • presence of risk factors
  • watery discharge
  • ropy, mucoid discharge
  • purulent discharge
  • itching predominant symptom
  • red eye
  • eyelids stuck together in morning
  • tender, pre-auricular lymphadenopathy

Other diagnostic factors

  • conjunctival follicles
  • chemosis
  • swollen eyelids
  • superficial punctate keratopathy
  • unilateral symptoms and signs
  • use of medications that may lead to eye irritation
  • contact lens use
  • corneal subepithelial infiltrates
  • corneal pannus
  • vesicular skin rash
  • symptoms and signs of related systemic disease

Risk factors

  • exposure to infected person
  • infection in one eye
  • environmental irritants
  • allergen exposure
  • concurrent infection
  • camps, swimming pools, military bases
  • Asian or Mediterranean boy or young man
  • atopic dermatitis
  • contact lens use
  • ocular prosthesis
  • trauma: mechanical, chemical, or ultraviolet
  • recent surgery or exposed sutures
  • hot, dry environment
  • rosacea
  • allogeneic stem cell transplantation
  • Stevens-Johnson syndrome/toxic epidermal necrolysis (TEN)
  • prior infection with herpes simplex virus
  • in neonate: vaginal delivery
  • oculogenital spread
  • asthma
  • hay fever
  • topical eye medicine
  • oral antihistamine/anticholinergic drugs
  • neoplasia
  • history of rheumatological disease
  • dysthyroid states
  • immunocompromised state
  • vasculitis
  • nasolacrimal duct obstruction
  • abnormality of supporting structures of the eye (adnexa)
  • severe tear deficiency
  • trauma

Diagnostic investigations

Investigations to consider

  • cell culture
  • special stains (Gram, Giemsa)
  • polymerase chain reaction
  • ocular pH
  • allergy skin testing
  • tear immunoglobulin E level

Treatment algorithm



Robert Sambursky, MD

Fellowship-Trained Ophthalmologist

Manatee Sarasota Eye Clinic & Laser Center




RS is employed by Lumos Diagnostics and serves on the board of Lumos Diagnostics, Visus Therapeutics, and PPK Solutions.


Dr Robert Sambursky would like to gratefully acknowledge Dr Lee Raykovicz, a previous contributor to this topic.


LR is Director of Clinical Relations, Rapid Pathogen Screening, Inc.

Peer reviewers

Michael Ehrenhaus, MD


Cornea, External Disease & Refractive Surgery

Long Island College Hospital Eye Center

Assistant Professor of Ophthalmology

SUNY Downstate Medical Center




ME declares that he has no competing interests.

Scott Fraser, MD, FRCS (Ed), FRCOphth

Consultant Ophthalmologist

Sunderland Eye Infirmary




SF declares that he has no competing interests.

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