Why does my sneeze smell bad? An expert explains

Although criticized as a haven for misogynists and white supremacists, Reddit also provides a space for people to ponder some of life’s burning questions. Among the most popular: Why does my sneeze smell weird?

One Redditor likened the odor of their sneezes to “metal and chemicals,” and another to “musk and dead animal.” (Lovely.) Some speculated that a stanky sneeze indicated a sinus infection or tonsillitis. Before spiraling down too deep a Reddit wormhole, I consulted an expert — Vijay Ramakrishnan, an otolaryngology (the study of conditions of the head and neck) expert — about whether a foul-smelling sneeze really does mean you’re sick.

Let’s back up and start with why you sneeze. Sneezing allows your nose or airway to get rid of an irritant, like smoke or dust, says Ramakrishnan, who is also a professor at the University of Colorado Anschutz Medical Campus. Usually, it’s a sign of irritation, not infection. “The nose is basically the initial filter that separates your lungs and respiratory system from the environment,” he explains, trapping pollutants and irritants from the air.

Usually, it’s a sign of irritation, not infection.

When you breathe, air flows smoothly in and out of your nose, Ramakrishnan says. But when you sneeze, you expel air and change up that flow, forcing odorous particles in your nose or throat upward to the olfactory nerve high in the nasal cavity, which transmits information about smell to the brain. A nasty stench after you sneeze, then, doesn’t mean you’re sick, per se. “I don’t think it’s necessarily a bad sign,” Ramakrishnan says, just odorants reaching the olfactory nerve that wouldn’t have otherwise. As a result, “you smell stuff you don’t normally smell.”

Where could those smells come from, though? A sinus infection — the explanation many Redditors have offered — is a possibility, but Ramakrishnan points out that sneezing isn’t one of the classic symptoms of this condition, which include stuffiness, facial pressure, and a constant foul odor. Likewise, it’s not a classic symptom of tonsillitis, another explanation Reddit users have suggested, which include a sore throat, fatigue, and fever. Some people with tonsillitis have bad breath, but not all. A dental infection might also explain why your sneezes reek, Ramakrishnan says.

He tells me that tonsil stones, which at least one Redditor has suggested, could be a culprit, too. These are calcium deposits that form when food or debris accumulate and harden in the crevices of your tonsils, according to the Cleveland Clinic — and they can stink. “But they smell bad all the time,” not just when you sneeze, Ramakrishnan says.

A less likely explanation is phantosmia, when you smell something that isn’t there, he adds. The Mayo Clinic explains that this condition may surface in the wake of an upper respiratory infection or head injury, and that more serious causes could include Parkinson’s disease or temporal lobe seizures. Parosmia, which affects how your brain processes smells — so that strawberries smell like, say, skunk — might also be possible, Ramakrishnan says. It can emerge alongside the olfactory dysfunction that may follow severe respiratory infection, per the Mayo Clinic.

A dental infection might also explain why your sneezes reek.

But pinpointing a definitive cause depends on what else you’re experiencing in addition to your gross-smelling sneezes, Ramakrishnan says. He explains that if someone were to visit a clinic reporting a stinky sneeze and no other symptoms, and their nose and mouth looked fine, the doctor would basically pat their back and send them on their way. In other words, if it’s your only complaint, you probably have nothing to worry about.

That said, contact you doctor if you’re sneezing all the time, if the odor is particularly bothersome, or if you have accompanying symptoms, such as nasal, sinus, dental, or neurological issues, Ramakrishnan says.

Amid current COVID-19 social distancing measures, he suggests a telehealth visit to start. Rather than using Reddit to self-diagnose — and possibly freaking yourself out in the process — you can work with a professional to begin the process of piecing together what your smelly sneezes really mean.