Allergic Conjunctivitis Differential Diagnoses

Updated: Jun 08, 2017
  • Author: Mark Ventocilla, OD, FAAO; Chief Editor: Andrew A Dahl, MD, FACS  more...
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Diagnostic Considerations

Allergic conjunctivitis must be differentiated from viral and bacterial conjunctivitis. Clinical features (eg, recent exposure to an individual with infective conjunctivitis) may be helpful in this regard.

The main distinction between seasonal and perennial allergic conjunctivitis, as implied by the names, is the timing of symptoms (see Pathophysiology). Major differentiating factors between vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC) are shown in the table below.

Table. Major Differentiating Factors Between VKC and AKC (Open Table in a new window)

Characteristics VKC AKC
Age at onset Generally presents at a younger age than AKC' first decade Second to third decade
Sex Males are affected preferentially. No sex predilection
Seasonal variation Typically occurs during spring months Generally perennial
Discharge Thick mucoid discharge Watery and clear discharge
Conjunctival scarring Moderate incidence of conjunctival scarring Higher incidence of conjunctival scarring
Horner-Trantas dots Horner-Trantas dots and shield ulcers are commonly seen. Presence of Horner-Trantas dots is rare.
Corneal neovascularization Not present, unless secondary to infectious keratitis Deep corneal neovascularization tends to develop
Presence of eosinophils in conjunctival scraping Conjunctival scraping reveals eosinophils to a greater degree in VKC than in AKC Presence of eosinophils is less likely

Differential Diagnoses