How can I tell if my itchy eyes are from allergies or a cold?

Itchy eyes almost always mean allergies, not a cold. Allergies last weeks and return seasonally, while a cold peaks at day 3–4 and clears in 7–10 days. Colds bring sore throat, fever, and colored mucus; allergies cause clear discharge and sneezing when outdoors. Best OTC treatment: a non-drowsy antihistamine like cetirizine or loratadine plus a nasal steroid spray like fluticasone for a week, adding ketotifen eye drops if needed.