Recent research suggests a surprising, though tentative, connection between frequent nose-picking and an increased risk of Alzheimer’s disease. A study conducted on mice reveals that Chlamydia pneumoniae, a bacterium common in human brains affected by late-onset dementia, can travel directly from the nasal cavity to the brain via the olfactory nerve—especially when the nasal lining is damaged.
The Pathogen’s Route to the Brain
The study, led by neuroscientist James St John at Griffith University in Australia, demonstrated that C. pneumoniae can reach the brain within 24-72 hours in mice. Damaged nasal tissue, such as that caused by picking or plucking, provides an easier pathway for the bacteria to enter the central nervous system. Once inside, the bacteria triggers the deposition of amyloid-beta proteins, which form plaques heavily linked to Alzheimer’s disease in humans.
“We’re the first to show that Chlamydia pneumoniae can go directly up the nose and into the brain where it can set off pathologies that look like Alzheimer’s disease,” St John stated.
Why This Matters
Alzheimer’s is a leading cause of death and disability, and its exact origins remain elusive. This research doesn’t prove that nose-picking causes Alzheimer’s, but it identifies a plausible biological mechanism linking common behavior to neurodegenerative disease. The olfactory system, already known for its direct connection to the brain, may serve as an underappreciated entry route for pathogens.
What the Research Shows
Researchers at Western Sydney University expanded on these findings in 2023, reinforcing that the olfactory system represents a “plausible route for pathogen entry” in Alzheimer’s development. They propose that improved hand hygiene—a lesson learned from the COVID-19 pandemic—could act as a simple preventative measure.
The speed at which C. pneumoniae colonizes the brain in mice suggests that this pathway could be significant even in humans, but further investigation is needed to confirm the same effects.
The Next Steps
St John and his team are planning human studies to validate their findings. Currently, they advise against damaging the nasal lining through picking or plucking, as this increases the risk of bacterial entry. The question of whether amyloid-beta plaques are a cause or a consequence of infection also remains open for further research.
This study highlights the complex interplay between environmental factors, bacterial infections, and neurodegenerative disease. Understanding these connections could unlock new prevention strategies for Alzheimer’s, but further research is essential to confirm these findings in human populations.
