Sinusitis is an inflammation of the sinus cavities that affects over 16 million people annually in doctor visits in America alone. The sinuses normally produce mucus to trap dust and germs, but sinusitis occurs when the mucus flow is blocked, allowing infection to develop from viruses, bacteria, or fungi. Common symptoms of sinusitis include blocked nose, cough, facial pressure or swelling, pain around the cheeks, eyes or forehead, sinus headaches, toothaches, discolored post-nasal drip, and loss of smell or taste. Chronic sinus problems are often caused by fungal infections. Left untreated, a sinus infection can potentially spread to the brain.