Sinusitis

A sinus infection causes your sinuses and nasal passages to become inflamed, and this inflammation is called sinusitis. The sinuses are small air pockets located behind your forehead, nose, cheekbones, and in between the eyes. The sinuses produce mucus, which is a thin and flowing liquid that protects the body by trapping and moving germs away. Sometimes, bacteria or allergens can cause too much mucus to form, which blocks the openings of your sinuses.