Which symptom is characteristic of allergic conjunctivitis?

• A. Itching
• B. Sudden vision loss
• C. Severe eye pain
• D. Hyphema

Answer: (A)

Allergic conjunctivitis is driven by an IgE-mediated reaction on the ocular surface, causing mast cell degranulation and the release of histamine. This leads to itching as a dominant symptom, often accompanied by redness, tearing, and swollen conjunctiva. The intense itching reflects irritation of the conjunctival nerves due to the allergic mediators, which is a hallmark of this condition rather than an infection or injury. Sudden vision loss would suggest something more serious like a retinal or optic nerve issue; severe eye pain points toward keratitis, uveitis, or glaucoma; and hyphema indicates trauma. So the presence of itching most clearly aligns with an allergic conjunctivitis diagnosis.