Ophthalmology Search
Ophthalmology Ophthalmology
conjunctivitis%20-%20allergic,%20seasonal%20-and-%20perennial
CONJUNCTIVITIS - ALLERGIC, SEASONAL & PERENNIAL

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.

Introduction

Seasonal Allergic Conjunctivitis (SAC)
  • Most common form of allergic conjunctivitis in temperate climates
  • Usually occurs & recurs at a certain period of the year (eg summer)
  • Subjectively more severe than PAC

Perennial Allergic Conjunctivitis (PAC)

  • Manifests & recurs throughout the year with no seasonal predilection
  • Most common in tropical climates

Pathophysiology

  • Direct exposure of ocular mucosal surfaces to the environment that causes an immediate hypersensitivity reaction in which triggering antigens couple to reaginic antibodies (IgE) on the cell surface of mast cells & basophils, leading to the release of histamines that causes capillary dilation & increased permeability &, thus, conjunctival injection & swelling
    • Nerve endings are also stimulated causing pain & itching

Signs and Symptoms

  • Ocular/periocular itching with redness, tearing, burning, stinging, photophobia, watery discharge, &/or ecchymosis (“allergic shiner”), foreign body sensation; characterized by exacerbations & remissions
    • Itching is considered the cardinal symptom
    • Identify the date & timing of onset, & progress of symptoms
    • Symptoms tend to decrease with age
Editor's Recommendations
Most Read Articles
Vitamin D supplementation confers no benefit for foetal, infant growth
3 days ago
Prenatal and postpartum vitamin D supplementation does not appear to improve foetal or infant growth, a study reports.
Excessive daytime sleepiness predicts Aβ deposition
5 days ago
Excessive daytime sleepiness appears to increase the long-term risk of amyloid β (Aβ) deposition, a recent study has shown.
Replacing carbohydrates with monounsaturated fatty acids does not reduce blood pressure
5 days ago
Substituting diets high in carbohydrates with those high in monounsaturated fatty acids in the context of low saturated fatty acids do not appear to yield favourable effects on blood pressure, according to a meta-analysis.
Mild cognitive impairment less likely to develop in obese, diabetic women than men
6 days ago
Among obese and overweight adults with type 2 diabetes mellitus, women appear to be less likely than men to develop mild cognitive impairment, independent of traditional risk factors, a recent study has shown.