Sneezes may stink because of a sinus infection. A common symptom of a sinus infection is the presence of thick, foul-smelling, nasal discharge, according to WebMD.
A sinus infection is inflammation of the sinuses caused by a blockage. The sinuses may become swollen and blocked when one has a cold. Cold symptoms usually go away on their own, but if the sinuses become blocked due to nasal congestion, the lack of airflow can lead to the development of a bacterial sinus infection, says WebMD. In addition to stinky sneezes, symptoms of a sinus infection include thick, yellow discharge; postnasal drip; headache; pain and pressure in the face around the eyes; cough; and fever.
These symptoms may also be present during a common cold, but if they occur during a sinus infection, the symptoms can linger and may not go away on their own. If symptoms are experienced for more than a week, make an appointment with a primary care physician, advises WebMD. If symptoms have not improved in 10 days, a physician can prescribe an antibiotic to fight the sinus infection. Other treatments may include over-the-counter decongestants and saline nasal sprays. A doctor may also recommend hot showers and steam treatments to loosen the mucus.