Picking your nose is a common habit, with studies suggesting nearly all adults engage in the practice occasionally. While often seen as an unsanitary social faux pas, this behavior compromises the body’s natural defenses. It facilitates the movement of harmful microorganisms, raising the likelihood of infection and the spread of pathogens. Health risks range from minor localized irritation to more serious, systemic bacterial infections.
The Nose’s Natural Defenses
The nasal cavity is the body’s first line of defense against airborne threats, acting as a sophisticated air filter. Specialized cells lining the nasal passages produce mucus, a sticky fluid composed of water, proteins, and antimicrobial agents. This mucus traps inhaled particles, including dust, pollen, and infectious pathogens, preventing them from reaching the lower respiratory tract. A healthy adult produces approximately 1.5 to 2 liters of this protective fluid daily.
Tiny, hair-like projections called cilia cover the epithelial cells within the nose. These cilia beat in a coordinated motion to propel the mucus blanket, along with trapped debris and microorganisms, toward the back of the throat. This process, known as mucociliary clearance, ensures that contaminated mucus is swallowed and destroyed by stomach acid or expelled. The natural flora of the nasal mucosa also contributes to defense by competing with invading bacteria.
Pathogens and Transmission Risk
Picking your nose directly interferes with natural defenses, creating two primary pathways for sickness. One pathway involves introducing external microorganisms from contaminated fingers. Hands frequently carry cold and flu viruses, and inserting a finger transfers these pathogens directly onto the nasal lining, bypassing the initial filtering action. The hands then become contaminated with nasal secretions, which can transfer back to the environment or to the mouth and eyes, which are other entry points for infection.
The second, more significant risk is disrupting the nose’s resident microbial population. A significant percentage of the population naturally carries the bacterium Staphylococcus aureus in the nose without symptoms. Studies show that people who pick their nose are significantly more likely to be nasal carriers of S. aureus. The physical manipulation can create tiny breaks or micro-abrations in the delicate mucosal lining, providing an entry point for these resident bacteria to move into the tissue and bloodstream. This habit also increases the total bacterial load of S. aureus, heightening the risk of infection.
Potential Health Consequences
The most common localized consequence of nose picking is minor trauma, such as nosebleeds from ruptured small blood vessels. Repeated irritation and the introduction of bacteria often lead to a localized infection called nasal vestibulitis. This condition causes painful inflammation, redness, and the formation of pimples or sores just inside the nostril opening, and is most often caused by the Staphylococcus aureus bacterium.
More serious health issues can arise when the local infection progresses beyond the nasal vestibule. If severe or untreated, it may develop into a boil or abscess, which can spread to surrounding facial tissues, leading to cellulitis. While rare, infections in this area are concerning because the veins connecting the nose to the brain have a direct path to the cavernous sinus. In extremely rare cases, typically in individuals with compromised immune systems, this can lead to cavernous sinus thrombosis or systemic infections like sepsis, especially if the bacteria involved is the antibiotic-resistant MRSA strain.