conjunctivitis%20-%20allergic,%20seasonal%20-and-%20perennial
CONJUNCTIVITIS - ALLERGIC, SEASONAL & PERENNIAL
Treatment Guideline Chart

Conjunctivitis is the inflammation of the conjunctiva.

Allergic conjunctivitis happens when the direct exposure of the ocular mucosal surfaces to the environment causes an immediate hypersensitivity reaction in which triggering antigens couple to reaginic antibodies (IgE) on the cell surface of mast cells and basophils, leading to the release of histamines that causes capillary dilation and increased permeability and thus conjunctival injection and swelling.
Seasonal allergic conjunctivitis is the most common form of allergic conjunctivitis in temperate climates. It usually occurs and recurs at a certain period of the year (eg summer).
Perennial allergic conjunctivitis manifests and recurs throughout the year with no seasonal predilection. It is most common in tropical climates.

Conjunctivitis%20-%20allergic,%20seasonal%20-and-%20perennial Diagnosis

Diagnosis

  • Allergic conjunctivitis are usually diagnosed by history and clinical presentation

History

  • Personal or family history of other allergic conditions (eg atopic dermatitis, allergic rhinitis, asthma)

Determine Possible Trigger Factors

  • Review history with regards to:
    • History of exposure to allergens
    • Occupational exposure
    • Travel
    • Use of eye care products, topical medications, solutions or contact lenses

Physical Examination

  • Clinical signs are usually bilateral and vary based on patient’s age, mediating cell type and association with other conditions
  • Conjunctival chemosis, hyperemia and a predominantly papillary conjunctival reaction
  • Slit-lamp biomicroscopy may be done to confirm or rule out diagnosis and exclude complications from other forms of ocular allergies

Laboratory Tests

  • Rarely needed to make diagnosis of SAC or PAC 
  • Usually done for academic or confirmatory purposes

Allergy Skin Testing

  • Skin prick testing and pollen IgE determination help to identify specific target allergens for immunosuppression
  • May consider serum specific IgE measurement if skin testing is not advised (eg patients on antihistamine) or contraindicated or results are inconclusive (eg presence of dermatographism)

Conjunctival Allergen Challenge

  • Also known as conjunctival allergen provocation test (CAPT)
  • A procedure wherein the conjunctiva is subjected to undergo exposure to increasing levels of a particular antigen (to which the patient previously had a positive skin test) until an ocular reaction is observed
  • For determination of ocular hypersensitivity conditions that are IgE-mediated
  • Usually used in studies
  • Indications:
    • For allergen identification
    • To evaluate inconsistency between history and allergen sensitization
    • To gauge the effectiveness of immunotherapy prior to allergy season
    • To evaluate drug therapies
  • Contraindications:
    • Performed within the pollen season
    • Medication that can affect allergen response
    • Other ocular disorders
    • Ocular surgery in the past 6 months
    • Uses contact lens
    • Pregnant and lactating women
    • Uncontrolled and severe systemic diseases-
    • Allergy to medications used during or after CAPT
    • Ocular disorders that are non-IgE-mediated
  • Primary results: Ocular pruritus (evaluated by the patient) and erythema (evaluated by the physician)
  • Secondary results (which are not always present in a positive CAPT): Lacrimation, eyelid edema and conjunctival chemosis

Conjunctival Scrapings

  • If positive for eosinophils it is strongly suggestive of allergy
  • Negative scraping is inconclusive

Cytological Exam of Tear Fluid

  • Collect tear sample with capillary tube, then spread on slide and stain
  • Allergic response is indicated by presence of eosinophils, neutrophils and/or lymphocytes
    • Tear histamine or tryptase levels can also be measured

Immunoassay Testing of Tear Fluid

  • Measure mast cell’s activity by determining the level of tryptase using immunoassay testing
  • IgE measured in tears may be used in diagnosing allergic conjunctivitis and in evaluating its severity
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