The skin around the nose and the nasal passages contain different types of bacteria. One commonly discussed example is Staphylococcus aureus.
This bacterium can live in the nose without causing any symptoms. Many healthy people carry it without ever developing an infection.
Problems can occur when bacteria enter damaged tissue.
For example, repeated scratching may create tiny openings in the skin around the nostrils. Bacteria can enter these openings and sometimes cause a condition called nasal vestibulitis.
Nasal vestibulitis is an infection or inflammation affecting the entrance of the nostrils.
Possible symptoms include:
-
Redness around the nostril opening.
-
Pain or tenderness when touching the nose.
-
Small pimples or sores.
-
Crusting around the nasal entrance.
-
Minor bleeding.
-
Swelling or discomfort.
Most cases can be treated successfully with appropriate medical care, but infections should not be ignored, particularly when symptoms become severe or spread.
In rare situations, infections involving the central facial region can develop serious complications.
This is another reason why maintaining healthy nasal hygiene matters.
5. Can Bacteria Really Travel From the Nose to the Brain?
This is one of the most important questions behind the scientific discussion.
The olfactory system has a direct anatomical relationship with the brain. Olfactory nerve fibers extend from the nasal cavity toward the olfactory bulb, allowing the brain to receive information about smells.
Scientists have investigated whether certain pathogens can exploit this pathway.
Some microorganisms have demonstrated the ability to interact with nervous tissue through routes involving the nose in experimental models.
However, the human body has multiple protective defenses, and the existence of an anatomical pathway does not mean that infections routinely travel through it.
The possibility of a microorganism entering the nervous system is also different from the possibility of that microorganism causing a chronic neurological disease.
For Alzheimer's disease, scientists are investigating several potential contributors, including:
-
Amyloid-beta accumulation.
-
Abnormal tau protein.
-
Chronic neuroinflammation.
-
Genetic susceptibility.
-
Vascular and metabolic health.
-
Aging and environmental factors.
-
Possible interactions between infections and the immune system.
No single explanation accounts for every case.
It is also important to recognize that Alzheimer's disease develops over many years. Its underlying biological changes may begin long before someone notices memory problems.
Consequently, scientists are studying whether infections could act as one contributing factor in susceptible individuals rather than assuming that one particular exposure is responsible for the disease.
6. Why Alzheimer's Disease Is So Difficult to Prevent and Treat
Alzheimer's is a progressive brain disorder that gradually affects the networks responsible for memory, reasoning, communication, and independent living.
The disease is associated with several biological changes.
Two of the most widely recognized are amyloid plaques and tau tangles.
Amyloid plaques consist of abnormal accumulations of amyloid-beta protein outside brain cells. Tau tangles develop when tau proteins become abnormally altered and accumulate inside neurons.
These changes are associated with damage to communication between brain cells and, eventually, the loss of neurons.
As the disease progresses, different areas of the brain may become affected.
The earliest noticeable symptoms often involve difficulty remembering recent information.
Over time, a person may struggle with familiar tasks, recognizing places, managing finances, following conversations, or remembering important events.
There is currently no treatment that completely cures Alzheimer's disease.
However, medical care has advanced considerably. Certain medications can help manage symptoms, while newer treatments targeting amyloid-beta may slow disease progression in some carefully selected people with early Alzheimer's.
These treatments do not restore all lost brain function, and they are not appropriate for every patient.
Researchers continue investigating additional treatments that could address the underlying biological processes involved in the disease.
This complexity explains why it is important not to interpret preliminary infection research as proof that a simple behavior directly causes an incurable neurological condition.
7. Why Changes in Your Sense of Smell May Deserve Attention
Another interesting aspect of Alzheimer's research involves the sense of smell.
Some people with neurodegenerative diseases experience changes in their ability to recognize or identify familiar odors.
This phenomenon is known as olfactory dysfunction.
A person may notice that coffee no longer smells as strong as it once did, familiar foods seem less aromatic, or certain odors become difficult to identify.
In some cases, changes in smell can appear before more obvious cognitive symptoms.
Scientists have investigated this relationship because areas involved in processing smell, including the olfactory bulb and nearby brain regions, can be affected by neurodegenerative processes.
However, a reduced sense of smell does not automatically indicate Alzheimer's disease.
There are many other possible explanations, including:
-
Viral respiratory infections.
-
Chronic sinusitis.
-
Nasal polyps.
-
Allergic rhinitis.
-
Smoking.
-
Certain medications.
-
Head injuries.
-
Other neurological conditions.
-
Normal age-related changes.
For example, some people experience a temporary or prolonged loss of smell after COVID-19 or another respiratory infection.
Others develop reduced smell sensitivity because inflammation or physical obstruction prevents odor molecules from reaching the olfactory receptors.
If you notice a persistent or unexplained change in your ability to smell, particularly if it occurs alongside other neurological symptoms, consider discussing it with a healthcare professional.
A proper assessment can help identify the underlying cause.