In allergic conjunctivitis, which treatment is contraindicated due to risk of rebound hyperemia?

• A. Saline solution or artificial tears.
• B. Topical mast cell stabilizer.
• C. Topical vasoconstrictor drops.
• D. Topical NSAID drops.

Answer: (C)

Topical vasoconstrictor drops reduce redness by narrowing conjunctival vessels, but they don’t treat the underlying allergic inflammation. With repeated use, the vessels become dependent on the drug, and when you stop the drops the vessels dilate again, often even more than before, leading to rebound redness and masking ongoing irritation. That rebound hyperemia is the reason these drops are avoided in allergic conjunctivitis. Other options are safer long-term: saline or artificial tears lubricate and help flush out allergens, while mast cell stabilizers address the inflammatory process by preventing mediator release.