Can Picking Your Nose Make You Sick?

Picking your nose can absolutely make you sick. Your fingers carry bacteria, viruses, and other pathogens, and pushing them past the thin, blood-vessel-rich lining of your nasal passages gives those organisms a direct route into your body. Research has linked nose picking to higher rates of bacterial colonization, increased respiratory infections, and, in rare cases, dangerous complications. The risks are real, though context matters: how often you pick, how clean your hands are, and whether you damage the tissue all change the equation.

What Lives Under Your Fingernails

The space beneath your fingernails is one of the dirtiest places on your body. A study of hand microflora found that the subungual space, the area right under the nail, harbored bacteria at concentrations roughly a hundred times higher than other parts of the hand.¹ That tight, warm, moist crevice is difficult to clean even with careful handwashing, and it shelters a variety of organisms including staphylococci, gut bacteria, and other potentially harmful species.

A separate assessment of fingernail contents found that about 30% of subjects carried culturable bacteria under their nails, including Staphylococcus aureus, E. coli, Klebsiella, and Pseudomonas. People with longer fingernails had significantly higher bacterial isolation rates than those who kept their nails trimmed short.² When you stick a finger into your nose, everything clinging to that nail tip gets deposited onto a warm, moist mucous membrane with a rich blood supply, an ideal landing zone for infection.

Hand-to-Nose Transmission of Respiratory Infections

A large share of respiratory infections spread not through coughs or sneezes alone, but through contaminated hands touching the face. People touch their faces constantly throughout the day, and the nostrils are one of the key entry points for pathogens picked up from surfaces.³ Nose picking intensifies this risk because it bypasses the external skin and delivers whatever is on your finger directly to the nasal mucosa.

Classic experiments with rhinoviruses, the main cause of the common cold, demonstrated just how efficient this route is. When volunteers touched hands that had been contaminated with rhinovirus and then touched their own noses or eyes, 11 out of 15 developed infections. By comparison, exposure through inhaled droplets in the air produced almost no infections at all.⁴ The hand-to-nose route was, in that study, by far the dominant way colds actually spread.

This pattern holds for bacteria too. In a controlled human infection study, researchers applied pneumococcus (the bacterium behind many cases of pneumonia and meningitis) to volunteers’ hands and then had them either sniff it or poke it into their nose. The “wet poke” group, who directly inserted bacteria-laden fingers into their nostrils, had the highest colonization rate at 40%. Those who sniffed wet bacteria from the back of their hand came in at 30%. Crucially, when the bacteria were allowed to dry on the skin before contact, colonization dropped dramatically, to 10% or zero.⁵ The message is clear: moist, fresh contamination on a finger that goes into the nose is a remarkably effective way to establish a bacterial foothold.

Nose Picking and SARS-CoV-2

The COVID-19 pandemic prompted researchers to look at whether nose picking might influence infection rates in a real-world setting. A cohort study of hospital healthcare workers tracked SARS-CoV-2 infections over about seven months in 2020. About 85% of the workers admitted to picking their nose at least occasionally. Those who did had roughly three times the odds of becoming infected with SARS-CoV-2 compared to those who said they never picked, even after adjusting for workplace exposure to COVID-19 patients.⁶

The study was observational, so it does not prove nose picking caused the infections. People who pick their noses may also touch their faces in other ways, or may be less meticulous about hand hygiene generally. Still, the finding aligns with the broader body of evidence that hand-to-nose contact is a meaningful transmission route for respiratory pathogens.

Staphylococcus aureus and Nasal Carriage

Your nose is already home to a diverse community of bacteria, and one of the most significant residents is Staphylococcus aureus. Roughly a quarter to a third of people carry this bacterium in their nostrils at any given time without symptoms. But nose picking appears to boost that number and increase how much of the bacterium is present.

A study of ear, nose, and throat patients and healthy volunteers found that nose pickers were about 50% more likely to carry S. aureus than non-pickers. Among the healthy volunteers, there was a clear dose-response relationship: the more frequently people reported picking their nose, the more often cultures came back positive and the higher the bacterial load.⁷ This matters because nasal carriage of S. aureus is a well-established risk factor for skin infections, surgical site infections, and, in hospital settings, the spread of drug-resistant strains like MRSA. You can carry S. aureus harmlessly for years, but the moment you undergo surgery, have a wound, or your immune system dips, that colonization can turn into an active infection.

How Picking Damages the Nasal Lining

Your nasal passages are lined with a mucous membrane equipped with tiny hair-like structures called cilia. Together, the mucus layer and the cilia form a conveyor belt that traps inhaled particles, bacteria, and viruses, then sweeps them toward the throat to be swallowed and destroyed by stomach acid.⁸ This system is your nose’s primary defense against infection, backed up by immune cells and antimicrobial proteins in the mucus itself.⁹

Picking your nose physically disrupts this defense. Fingernails can scratch, tear, or scrape the delicate mucosa, creating micro-wounds. Research using animal models has shown that when the nasal mucosa is wounded and then exposed to bacteria, biofilm formation occurs at rates that simply do not happen on intact tissue. In one experiment, biofilm growth was detected on wounded mucosa within days of bacterial exposure and progressively worsened over two weeks, while undamaged tissue showed no biofilm at all.¹⁰ Biofilms are clusters of bacteria encased in a protective matrix that makes them far more resistant to both your immune system and antibiotics. Once a biofilm establishes itself in your nose, clearing the infection becomes much harder.

Repeated picking, especially with long or jagged nails, can cause chronic irritation that never fully heals, creating a revolving door of small wounds and bacterial colonization. Nosebleeds are the most obvious sign of this damage, but even without visible bleeding, the tissue can be compromised enough to let pathogens in.

Rare but Serious Complications

For most people, nose picking causes no lasting harm beyond the occasional nosebleed or minor infection. But chronic, compulsive picking can lead to structural damage. A study of patients with self-induced nasal septal perforation, a hole through the cartilage wall between the nostrils, found that the overwhelming majority of these perforations were located toward the front of the septum, the area most accessible to a probing finger.¹¹ Septal perforations can cause whistling sounds during breathing, crusting, recurrent nosebleeds, and sometimes require surgical repair.

More alarming, though extremely uncommon, are deep infections that start in the nose and spread to the surrounding tissues. The nose sits in the middle of the face within a network of veins that connect to the cavernous sinus, a venous channel at the base of the brain. These veins lack the valves that veins elsewhere in the body have, which means infections can travel backward along them. A case series documented children who developed cavernous sinus thrombosis, a blood clot in that venous channel triggered by nasal infections, presenting with headaches, bulging eyes, restricted eye movement, and fever.¹² This is a life-threatening emergency. It is also vanishingly rare, but its existence underscores why doctors have long warned against picking at nasal sores or squeezing infected spots in the central face.

Parasites and Children

Nose picking poses a particular kind of risk for children because of a specific parasite: pinworms. Pinworm infection is the most common helminth infection in temperate countries, and its transmission cycle relies heavily on finger-to-mouth or finger-to-nose contact. Pinworm eggs are deposited around the anus, usually at night. When a child scratches, the eggs get under the fingernails. Those eggs can then be transferred to the mouth or nose by finger contact, completing the infection cycle. The main risk factors for pinworm infection include being between ages 4 and 11, nail-biting, and poor hand hygiene, all of which tend to overlap with frequent nose picking.¹³

For adults, pinworm is less of a concern, but the principle extends to other fecal-oral pathogens. Any situation where hands contact contaminated surfaces, and then fingers go into the nose, creates an opportunity for organisms that would otherwise never reach your respiratory or gastrointestinal mucosa.

The Alzheimer’s Hypothesis

One area of emerging (and still very speculative) research asks whether nose picking could play a role in neurodegenerative diseases. The olfactory system, the network of nerves responsible for your sense of smell, has a direct anatomical connection to the brain. It is one of the few places where nerve endings are exposed to the external environment, separated from the outside world by only a thin layer of mucosa high in the nasal cavity.

A 2023 narrative review proposed the hypothesis that pathogens including viruses, bacteria, and fungi might exploit the olfactory pathway to enter the brain and trigger neuroinflammation, potentially contributing to Alzheimer’s disease. The authors specifically flagged nose picking as one way contaminated material from hands, including soil and fecal organisms, could be introduced to the olfactory mucosa.¹⁴ This is an intriguing idea supported by the known anatomy, but it remains a hypothesis. No study has demonstrated a causal link between nose picking and Alzheimer’s in humans, and the authors were clear that this was a theoretical framework, not an established finding. It is worth being aware of, but not worth losing sleep over at this stage.

Almost Everyone Does It

If any of this has made you feel singled out, rest easy: nose picking is nearly universal. A survey published in the Journal of Clinical Psychiatry found that 91% of respondents were current nose pickers, though only 75% believed that “almost everyone does it.”¹⁵ A separate study of hospital healthcare workers found that 85% admitted to at least occasional nose picking, with doctors being the most frequent pickers (up to 100% among residents).⁶

For the vast majority of people, occasional nose picking is a benign habit. The risks escalate when picking is frequent, forceful, or done with unwashed hands. If you pick habitually and cannot stop despite social embarrassment or physical harm like chronic nosebleeds or sores, that tips into a recognized condition called rhinotillexomania, essentially compulsive nose picking. It sits alongside compulsive hair pulling and nail biting as a body-focused repetitive behavior that sometimes benefits from behavioral therapy.¹⁵

Practical Ways to Reduce the Risk

You are probably not going to stop entirely, and you do not necessarily need to. But a few habits can substantially lower the chances of nose picking making you sick:

Keep nails short: Shorter nails carry fewer bacteria, cause less tissue damage, and are easier to clean. The subungual space shrinks when nails are trimmed close, reducing the bacterial reservoir that gets deposited in your nose.
Wash your hands frequently: If your hands are cleaner going in, the risk drops. This matters most after touching shared surfaces, handling raw food, using the bathroom, or being in clinical settings.
Use saline spray or a tissue: If the urge to pick is driven by crusting or dryness, a saline nasal spray can loosen dried mucus and make it easier to clear with a gentle blow rather than a finger. A tissue at least puts a barrier between your nails and the mucosa.
Address underlying causes: Chronic nasal dryness, allergies, or deviated septum issues can all increase the urge to pick. Treating the underlying irritation reduces the behavior.

Nose Picking in Other Primates

If it offers any consolation, humans are not alone in this habit. A review of nose picking across primate species documented the behavior in multiple species and noted that several primates not only pick their noses but eat the mucus afterward.¹⁶ The aye-aye, a lemur with an extraordinarily long, thin middle finger, was observed inserting that finger deep into its nasal passages. Some researchers have speculated that ingesting nasal mucus could expose the immune system to small doses of trapped pathogens, functioning as a kind of low-grade immunological sampling. That idea remains unproven and somewhat tongue-in-cheek, but the cross-species prevalence of the behavior suggests it is deeply rooted in primate biology rather than simply a failure of manners.

1
PubMed Central. Composition and density of microflora in the subungual space of the hand
2
PubMed Central. Bacterial and Parasitic Assessment from Fingernails in Debre Markos, Northwest Ethiopia
3
PubMed Central. A study quantifying the hand-to-face contact rate and its potential application to predicting respiratory tract infection
4
PubMed. Hand-to-hand transmission of rhinovirus colds
5
European Respiratory Journal. Hands are vehicles for transmission of Streptococcus pneumoniae in novel controlled human infection study
6
PLoS ONE. Why not to pick your nose: Association between nose picking and SARS-CoV-2 incidence, a cohort study in hospital health care workers
7
PubMed. Nose picking and nasal carriage of Staphylococcus aureus
8
PubMed Central. Cilia and Mucociliary Clearance
9
PubMed Central. Non-Reflex Defense Mechanisms of Upper Airway Mucosa: Possible Clinical Application
10
PubMed Central. Bacterial biofilm formation after nasal packing in nasal mucosa-wounded mice
11
PubMed. Self-Induced Nasal Septal Perforation: Rhinotillexomania-A Different Entity From Nose Picking
12
PubMed Central. Cavernous sinus thrombosis of nasal origin in children
13
PubMed Central. The Diagnosis and Treatment of Pinworm Infection
14
PubMed Central. Neuroinflammation in Alzheimer’s Disease: A Potential Role of Nose-Picking in Pathogen Entry via the Olfactory System?
15
PubMed. Rhinotillexomania: psychiatric disorder or habit?
16
Journal of Zoology. A review of nose picking in primates with new evidence of its occurrence in Daubentonia madagascariensis