One of the principal
functions of the nose is to remove particles from the air before
it goes into the lungs.
The allergic response
It is one of a number
of mechanisms the body has to defend itself from the outside environment.
Foreign particles become trapped in the mucus lining of the nose
and are subsequently destroyed.
One of these involves
specific protein and chemical reactions within the body and is called
the allergic response. This specific mechanism can affect any area
of the body where a foreign substance is encountered.
Because of the amount
of foreign material processed in the nose, the allergic response
can become quite noticeable and troublesome.
Histamine is one of
the principal chemicals involved in the allergic response. It is
responsible for many of the symptoms of allergy, including swelling,
itchiness, and sneezing.
The allergic response
can also cause the overproduction of mucus, leading to a runny nose.
This is the reason that antihistamines, drugs that block the action
of this chemical, are often used in treating allergies. Other methods
of therapy include nasal steroid sprays or cromolyn nasal sprays.
Cromoglycate is a drug whose sodium salt is inhaled to prevent asthmatic
attacks and allergic reactions.
Common allergens are
dust mites, proteins from pet fur called dander, molds, and pollen.
Avoiding the specific item that provokes an allergic response -
called an allergen - is a key element in treatment.
In some cases the cause
is obvious, as when cutting the grass or petting the dog provoke
an allergic response. In others, the offending allergen may not
be so easily identified or there may be many allergens, complicating
the diagnosis and treatment of the problem.
In many cases, conferring
with an allergist can help find out the cause. After a thorough
history and physical examination, allergy testing may be warranted.
Occasionally, allergy shots can help to blunt the individual's reaction
to the allergen.
Allergic rhinitis is
associated with other conditions, such as asthma and sinusitis.
The lining of the nose, or mucosa, is made up of the same type of
cells as those that line the sinuses and lungs.