Rhinitis is one of the most commonly
encountered diseases in man, affecting about 23% of the adult
population. It is associated with symptoms including irritation and
inflammation of the nasal passages and may be associated with
conjunctivitis (an inflammation of the eyes). Rhinitis is not
always severe and is usually spontaneously reversible. It can be
caused by various agents such as viruses or allergens. Typically,
an affected individual will have 2 or 3 episodes of rhinitis per
year; mainly induced by viruses or "common colds".
Allergic rhinitis is often erroneously considered as a
relatively trivial disorder. In fact, it may have an impact on the
development or aggravation of asthma. Indeed, according to figures
from the World Health Organization, 80% of asthma patients have
previously presented with rhinitis.
Allergic rhinitis occurs in patients who have become sensitized
to an allergen. It is defined as a symptomatic disease of the nose
induced by direct contact between the nasal lining (or “mucosa”)
and, usually, an airborne allergen (link).. Subsequent exposure to
the allergen leads to further inflammation in the nose and
increased reactivity of the nose to other triggers such as tobacco
smoke or pollution. This phenomenon is called “nasal
hyperreactivity”.
Although it is not always considered by the public to be a severe
disease, allergic rhinitis is becoming a true public health problem
because:
- Its prevalence (the percentage of persons suffering from it) is
increasing and has reached epidemic levels
- It severely affects the quality of life of patients: impairment
of social life, decrease of productivity at work or in school
- It may lead to, or be associated with, conjunctivitis,
sinusitis, ear diseases, pharyngitis, bronchitis and also
asthma.
The main symptoms of allergic rhinitis are nasal itching,
sneezing, watery nasal discharge (runny nose or 'rhinorrhoea') or
obstructed nose (stuffy or blocked nose). These symptoms may
sometimes be accompanied by soreness of the throat; discomfort in
the ears; and ocular symptoms including conjunctivitis and oedema,
itchiness, and watery eyes.
Allergic rhinitis is generally classified according to the cause
and the duration of symptoms; distinguishing between "seasonal" and
"perennial" causes.
Seasonal allergic rhinitis (commonly known as “hay fever”) is
related to a wide variety of outdoor allergens such as pollens and
moulds which are encountered during a well-defined period of the
year.
Perennial allergic rhinitis is commonly caused by indoor allergens
such as dust mites, moulds, insects (acarians, cockroaches) and
animal dander. The patient may encounter these allergens all year
round in his home or working environment. The exposure provokes a
long-term or even permanent disease state.
However this classification into seasonal and perennial rhinitis
does not always fit with the daily experience of allergic patients
or with some recent scientific findings:
- Some pollen can be present in the air in a seasonal manner in
certain regions of the world, whilst they are continuously present
in other areas. This classification is thus not applicable
worldwide
- The classification does not take into account the effective
duration and frequency of symptoms experienced by the allergic
patient.
- Unfortunately, some patients can be allergic to a variety of
so-called "seasonal" allergens (polysensitization) which, finally,
provoke symptoms of rhinitis almost all year long.
- The severity of the disease is estimated according to the
severity of the main nasal symptoms rather than according to the
impact on the patient’s quality of
life.
For these reasons, a new classification of allergic rhinitis has
been proposed by ARIA ("Allergic Rhinitis and its Impact on
Asthma"; a working group of experts in the field of allergy and
supported by the Word Health Organization), redefining rhinitis as
either an "intermittent" or a "persistent" disease.
Intermittent Allergic Rhinitis: a brief description
Persistent Allergic Rhinitis: a brief description
As already mentioned, many factors can induce inflammation of
the nose. After taking the patient’s history and making a clinical
examination, the doctor will propose a series of tests to define
the cause of the rhinitis. If the results of these investigations
do not identify any allergic origin of the symptoms, the disease is
classified as non-allergic rhinitis.
Non-allergic rhinitis is generally characterised by the patient
exhibiting a poor sense of smell (hyposmia) or even no sense of
smell at all (anosmia) and a blocked nose (nasal obstruction).
Usually the symptoms of watery rhinorrhea (runny nose), sneezing
and itchy nose are also present.
The following types of non-allergic rhinitis can be
differentiated:
