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.

Conjunctivitis%20-%20allergic,%20seasonal%20-and-%20perennial Signs and Symptoms

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
Product Highlight - ADACEL
01 Dec 2020
Tetanus toxoid 5 Lf, diphtheria toxoid 2 Lf, pertussis toxoid 2.5 mcg, filamentous haemagglutinin 5 mcg, fimbriae types 2 and 3 5 mcg, pertactin 3 mcg
Spotlight on multidrug-resistant gram-negative infections: New developments for an old problem
Dr. Hsu Li Yang, Dr. Tan Thuan Tong, Dr. Andrea Kwa, 08 Jan 2021
Antimicrobial resistance has become increasingly dire as the rapid emergence of drug resistance, especially gram-negative pathogens, has outpaced the development of new antibiotics. At a recent virtual symposium, Dr Hsu Li Yang, Vice Dean (Global Health) and Programme Leader (Infectious Diseases), NUS Saw Swee Hock School of Public Health, presented epidemiological data on multidrug-resistant (MDR) gram-negative bacteria (GNB) in Asia, while Dr Tan Thuan Tong, Head and Senior Consultant, Department of Infectious Diseases, Singapore General Hospital (SGH), focused on the role of ceftazidime-avibactam in MDR GNB infections. Dr Andrea Kwa, Assistant Director of Research, Department of Pharmacy, SGH, joined the panel in an interactive fireside chat, to discuss challenges, practical considerations, and solutions in MDR gram-negative infections. This Pfizer-sponsored symposium was chaired by Dr Ng Shin Yi, Head and Senior Consultant of Surgical Intensive Care, SGH.
New asthma guide: What doctors should know
Pearl Toh, 26 Nov 2020
Inhaled corticosteroid (ICS) should be the mainstay of long-term asthma management — such is the key message of the latest Singapore ACE* Clinical Guidance (ACG) for asthma, released in October 2020.
Biologic treatments for psoriasis protect against COVID-19 hospitalization
4 days ago
Among patients with moderate-to-severe psoriasis, the use of biologics appears to lower the risk of being hospitalized for the novel coronavirus disease (COVID-19), a new study has found.