Can a sinus infection cause bad breath?

Sinusitis is swelling of the air-filled spaces behind your cheeks and forehead, usually after a cold. When the sinuses cannot drain properly, mucus builds up and can become thick and discolored. Three things then work against your breath:

• Infected mucus drains backward into your throat and onto the back of your tongue, where it can smell on its own and feeds odor-producing bacteria.
• A blocked nose pushes you to breathe through your mouth, especially at night. A dry mouth has less saliva to wash bacteria away.
• A reduced sense of smell is common with sinusitis, so you may not notice how strong your breath has become.

The NHS lists these sinusitis symptoms:

• Pain, swelling and tenderness around your cheeks, eyes or forehead
• A blocked or runny nose
• A reduced sense of smell
• Green or yellow mucus from your nose
• A high temperature
• Headache, toothache, bad breath or a cough

Young children may be irritable, have trouble feeding and breathe through their mouth. A study of adults with long-term (chronic) sinusitis found bad breath in about 41%, so it is a common complaint, not a rare one.

Upper back toothache is a sinusitis symptom, but tooth pain can also come from a dental problem, so see a dentist if the toothache stays after the sinus symptoms settle. If your bad breath continues after a sinus infection has cleared, look at post nasal drip or tonsil stones.

• Rinse your nose with salt water up to 3 times a day, using the NHS method with boiled and cooled water, or a pharmacy saline kit.
• Rest and drink plenty of fluids. Fluids help keep mucus thinner and your mouth moist.
• Use pain relief such as paracetamol (acetaminophen) or ibuprofen, following the label, if you need it.
• Clean your tongue and teeth well, especially the back of the tongue where mucus settles. This tackles the mouth part of the smell while you recover.
• Sip water at night and consider a humidifier if you wake with a dry mouth.

A pharmacist can suggest decongestant sprays or steroid nasal sprays. Mouthwash and mints only mask the odor for a short while.

Most sinusitis is caused by a virus and clears on its own, so antibiotics are rarely needed. If it is taking a long time to go away, a pharmacist or GP may prescribe steroid nasal sprays or drops. The NHS says a GP may refer you to an ear, nose and throat (ENT) specialist if you still have sinusitis after 3 months of treatment or keep getting it. Treating chronic sinusitis often improves the bad breath that comes with it.

The NHS advises seeing a GP if you do not improve after 3 weeks of treating symptoms yourself, after 7 days of treatment from a pharmacy or GP, or if you keep getting sinusitis. MedlinePlus advises contacting a provider if symptoms last longer than 10 to 14 days, a cold gets worse after 7 days, you have a fever or a severe headache that over-the-counter pain medicine does not relieve, or you notice any change in your vision. Complications are very rare but can include infection around the eye, so do not wait on eye swelling.