A physician should be consulted. When the nasal mucus turns from clear to yellow or green, it usually means that a bacterial infection has taken over and a physician should be consulted. Acute sinus infections produce nasal congestion, thick discharge, and pain and tenderness in the cheeks and upper teeth, between and behind the eyes, or above the eyes and in the forehead, depending on which sinuses are involved. Chronic sinus infections may or may not cause pain, but nasal obstruction and offensive nasal or postnasal discharge is often present. Allergy is an exaggerated inflammatory response to a foreign substance which, in the case of a stuffy nose, is usually a pollen, mold, animal dander, or some element in house dust.
Foods sometime play a role.
Ideally the best treatment is avoidance of these substances, but that is impractical in most cases. Decongestants help by shrinking the swollen nasal tissues so as to open the breathing passages. Therefore combinations of these two types of drugs are often the best solution since the desired effects complement each other and the side effects tend, at least to some degree, to cancel each other out. Patients who get sleepy from antihistamines should not drive an automobile or operate dangerous equipment after taking them. Pregnant patients should consult their obstetrician before taking any medicine.