A sinus infection, or sinusitis, often begins with subtle yet noticeable symptoms that can be mistaken for a common cold or allergies. The earliest signs typically include nasal congestion, facial pressure, and a mild headache, as inflammation in the sinuses leads to blocked airflow and mucus buildup. Other early indicators may involve postnasal drip, a sore throat, and a reduced sense of smell or taste. If left untreated, these symptoms can worsen, leading to more ...