Allergic Conjunctivitis Guideline

Introduction

• Allergic conjunctivitis is an inflammation of the conjunctiva caused by an IgE-mediated hypersensitivity reaction to environmental allergens, characterized by bilateral eye redness, itching, chemosis, and watery or mild mucous discharge, according to the American Academy of Ophthalmology 1
• Allergic conjunctivitis can be classified into several forms, including Seasonal/Perennial Allergic Conjunctivitis, Vernal Keratoconjunctivitis, and Atopic Keratoconjunctivitis, as stated by the American Academy of Allergy, Asthma, and Immunology 1, 2

Clinical Presentation

• Bilateral involvement is typically seen in allergic conjunctivitis, with intense itching being a hallmark symptom, according to the American Academy of Ophthalmology 1
• Conjunctival injection, chemosis, watery or mild mucous discharge, eyelid edema, periorbital hyperpigmentation, and papillary reaction of the palpebral conjunctiva are common signs and symptoms, as reported by the American Academy of Allergy, Asthma, and Immunology 1, 2

• Different types of conjunctivitis have distinct characteristics:

  Type	Characteristics
  Bacterial	Redness, purulent discharge, mattering and adherence of eyelids on waking, absence of itching
  Viral	Watery discharge, follicular reaction, preauricular lymphadenopathy, often follows upper respiratory infection
  Allergic	Severe itching, watery discharge, history of allergies
  Herpes Simplex	Unilateral with watery discharge and possible vesicular skin lesions

Diagnosis

• Diagnosis is primarily clinical, based on history, physical examination, and slit lamp examination, according to the American Academy of Ophthalmology 1
• A history of typical symptoms, seasonal patterns, known allergies, and association with rhinitis is essential for diagnosis, as stated by the American Academy of Allergy, Asthma, and Immunology 1, 2
• Biomicroscopy with a slit lamp is essential for evaluating the cornea, conjunctiva, and anterior chamber, and for differentiating between serious causes of red eye, as recommended by the American Academy of Ophthalmology 1, 3

Treatment

• Cold compresses and artificial tears/saline irrigation can provide symptomatic relief, according to the American Academy of Allergy, Asthma, and Immunology 2
• Treatment should follow a stepwise approach based on severity, with topical antihistamines, mast cell stabilizers, and dual-action agents being used for mild cases, as reported by the American Academy of Ophthalmology 1
• Oral antihistamines and intranasal corticosteroids can be effective for associated allergic rhinitis, according to the American Academy of Allergy, Asthma, and Immunology 2

• Specific treatments for different types of conjunctivitis:

  Type	Treatment
  Viral	Supportive care with artificial tears, cold compresses, and antihistamine eye drops for symptomatic relief
  Bacterial	Antibiotic therapy, such as fluoroquinolones, aminoglycosides, and macrolides
  Allergic	Antihistamines, mast cell stabilizers, and vasoconstrictors, with corticosteroids reserved for severe cases under ophthalmologic supervision
  Herpetic	Antiviral agents, such as acyclovir, either topically or orally, depending on the severity

Complications and Prevention

• Chronic forms of allergic conjunctivitis can lead to corneal complications, visual impairment, and reduced quality of life, according to the American Academy of Ophthalmology 1 and the American Academy of Allergy, Asthma, and Immunology 2
• Identifying and avoiding triggers, regular handwashing, proper contact lens care, and early intervention can help prevent complications, as stated by the American Academy of Ophthalmology 1
• Risk factors for conjunctivitis include contact with infected individuals, poor hygiene, inadequate use of contact lenses, immunosuppression, structural eyelid anomalies, severe tear deficiency, and ocular trauma, as identified by the American Academy of Ophthalmology 3
• Prevention measures include frequent handwashing, avoiding touching or rubbing eyes, using separate towels and pillows, proper disinfection of surfaces and equipment, and avoiding close contact during contagious period, as recommended by the American Academy of Ophthalmology 1, 3
• Red flag symptoms such as severe pain, sudden vision loss, or significant discharge may indicate bacterial keratitis or other sight-threatening conditions requiring immediate intervention, as suggested by the American Academy of Ophthalmology 4, 5
• Immediate referral is indicated for visual loss, moderate or severe pain, severe purulent discharge, corneal involvement, conjunctival scarring, lack of response to therapy, recurrent episodes, history of HSV eye disease, and immunocompromised patients, according to the American Academy of Ophthalmology 1