Sinus problems refer to conditions that affect the paranasal sinuses, the air-filled cavities within the bones of the face that help humidify and filter air, lighten the skull, and enhance voice resonance. Common sinus issues include sinusitis (inflammation or infection of the sinuses), allergic reactions, nasal polyps, and structural abnormalities such as a deviated septum. Symptoms may include nasal congestion, facial pain or pressure, headache, postnasal drip, reduced sense of smell, fever, or fatigue. Sinus problems can be acute, often following a cold or upper respiratory infection, or chronic, lasting weeks to months. Persistent or severe sinus symptoms may indicate underlying infection or structural issues that require medical evaluation.