Rhinorrhea or rhinorrhoea is a condition where the nasal cavity is filled with a significant
amount of mucus fluid.
The condition, commonly known as a "runny nose", occurs relatively frequently.
Rhinorrhea is a common symptom of allergies or certain diseases, such as the common cold
or hay fever.
It can be a side effect of crying, exposure to cold temperatures, cocaine abuse or withdrawal,
such as from opioids like methadone.
Treatment for rhinorrhea is not usually necessary, but there are a number of medical treatments
and preventive techniques available.
The term was coined in 1866 and is a combination of the Greek terms "rhino-" meaning "of the
nose" and "-rhoia" meaning "discharge or flow".
Signs and symptoms Rhinorrhea is characterized by an excess amount
of mucus produced by the mucous membranes that line the nasal cavities.
The membranes create mucus faster than it can be processed, causing a backup of mucus
in the nasal cavities.
As the cavity fills up, it blocks off the air passageway, causing difficulty breathing
through the nose.
Air caught in nasal cavities, namely the sinus cavities, cannot be released and the resulting
pressure may cause a headache or facial pain.
If the sinus passage remains blocked, there is a chance that sinusitis may result.
If the mucus backs up through the Eustachian tube, it may result in ear pain or an ear
infection.
Excess mucus accumulating in the throat or back of the nose may cause a post-nasal drip,
resulting in a sore throat or coughing.
Additional symptoms include sneezing, nosebleeds, and nasal discharge.
Causes Cold temperature
Rhinorrhea is especially common during winter months and certain low temperature seasons.
Cold-induced rhinorrhea occurs due to a combination of thermodynamics and the body's natural reactions
to cold weather stimuli.
One of the purposes of nasal mucus is to warm inhaled air to body temperature as it enters
the body.
In order for this to happen, the nasal cavities must be constantly coated with liquid mucus.
During cold, dry seasons, the mucus lining nasal passages tends to dry out, meaning that
mucous membranes must work harder, producing more mucus to keep the cavity lined.
As a result, the nasal cavity can fill up with mucus.
At the same time, when air is exhaled, water vapor in breath condenses as the warm air
meets the colder outside temperature near the nostrils.
This causes an excess amount of water to build up inside nasal cavities.
In these cases, the excess fluid usually spills out externally through the nostrils.
Infection Rhinorrhea can be a symptom of other diseases,
such as the common cold or influenza.
During these infections, the nasal mucous membranes produce excess mucus, filling the
nasal cavities.
This is to prevent infection from spreading to the lungs and respiratory tract, where
it could cause far worse damage.
It has also been suggested that Rhinorrhea is a result of viral evolution, and may be
a response that is not useful to the host, but which has evolved by the virus to maximise
its own infectivity.
Rhinorrhea caused by these infections usually occur on circadian rhythms.
Over the course of a viral infection, sinusitis may occur, causing the mucous membranes to
release more mucus.
Acute sinusitis consists of the nasal passages swelling during a viral infection.
Chronic sinusitis occurs when one or more nasal polyps appear.
This can be caused by a deviated septum as well as a viral infection.
Allergies
Rhinorrhea can also occur when individuals with allergies to certain substances, such
as pollen, dust, latex, soy, shellfish, or animal dander, are exposed to these allergens.
In people with sensitized immune systems, the inhalation of one of these substances
triggers the production of the antibody immunoglobulin E, which binds to mast cells and basophils.
IgE bound to mast cells are stimulated by pollen and dust, causing the release of inflammatory
mediators such as histamine.
In turn, this causes, among other things, inflammation and swelling of the tissue of
the nasal cavities as well as increased mucus production.
Particulate matter in polluted air and chemicals such as chlorine and detergents, which can
normally be tolerated, can make the condition considerably worse.
Lacrimation Rhinorrhea is also associated with shedding
tears, whether from emotional events or from eye irritation.
When excess tears are produced, the liquid drains through the inner corner of the eyelids,
through the nasolacrimal duct, and into the nasal cavities.
As more tears are shed, more liquid flows into the nasal cavities.
The buildup of fluid is usually resolved via mucus expulsion through the nostrils.
Head trauma
If caused by a head injury, rhinorrhea can be a much more serious condition.
A basilar skull fracture can result in a rupture of the barrier between the sinonasal cavity
and the anterior cranial fossae or the middle cranial fossae.
This rupture can cause the nasal cavity to fill with cerebrospinal fluid.
This condition, known as cerebrospinal fluid rhinorrhoea or CSF rhinorrhea, can lead to
a number of serious complications and possibly death if not addressed properly.
Other causes Rhinorrhea can occur as a symptom of opioid
withdrawal accompanied by lachrymation.
Other causes include cystic fibrosis, whooping cough, nasal tumors, hormonal changes, and
cluster headaches.
Rhinorrhea can also be the side effect of several genetic disorders, such as primary
ciliary dyskinesia.
Treatment In most cases treatment for rhinorrhea is
not necessary since it will clear up on its own—especially if it is the symptom of an
infection.
For general cases, blowing your nose can get rid of the mucus buildup.
Alternatively, saline nasal sprays and vasoconstrictor nasal sprays may also be used, but may become
counterproductive after several days of use, causing rhinitis medicamentosa.
In recurring cases, such as those due to allergies, there are medicinal treatments available.
For cases caused by histamine buildup, several types of antihistamines can be obtained relatively
cheaply from drugstores.
People who prefer to keep clear nasal passages, such as singers, who need a clear nasal passage
to perform, may use a technique called "nasal irrigation" to prevent rhinorrhea.
Nasal irrigation involves rinsing the nasal cavity regularly with salty water or store
bought saline solutions.
References
External links Runny Nose: A Guide for Parents at the Wayback
Machine from the Pennsylvania Medical Society Cold and flu advice
How to Wipe Your Nose How to Wipe Your Nose on Your Hands