Allergic
rhinitis is a combination of two or more nasal symptoms which are running nose,
nasal blockage, itching or sneezing. It occurs when symptoms are as a result of
IgE mediated inflammation following exposure to allergens.
It is a
global health problem with increasing prevalence. It can be mild whereby you
have normal sleep, doesn’t impair daily activities, normal work and school
functions and no troublesome symptoms. It can also be moderate-severe where it
affects sleep, impairs daily activities and causes problems at school and work
and have troublesome symptoms.
One of the
risk factors causing it is family history and genetics. Family history of
allergic rhinitis is common in many cases. Several genes appear to be involved
in atopy and these include an area on 5q chromosome where genes exist for IL-4
and IL-13. Others are on IL 11q and 13q. Another risk factor is the
environment. This includes pollution especially in urban areas and irritants.
Lifestyle changes which have led to unhealthy foods and caused obesity have
increased the risk of allergic rhinitis.
There are
other conditions which have been associated with allergic rhinitis include
asthma, sinusitis, otitis media and lower respiratory tract infections. The
pathophysiology of allergic rhinitis is in four phases – sensitization, early
phase reaction, late phase reaction and systemic reaction.
Clinically
they present with sneezing, running nose, itching, nasal blockage or loss of
sense of smell. On examination they may have an allergic crease and allergic
salute. The nasal mucosa is usually swollen, pale or bluish in color, edematous
and covered with watery secretions.
Skin prick
tests are now done - they are simple, relatively cheap and fast. An allergen is
placed on the skin and a reaction is observed. If the diameter is more than 2mm
in children under 5yrs or more than 3mm in older children and adults then its
considered positive. Blood tests that can be done usually involve IgE titres
measured by Cap RAST testing but is more expensive.
Treatment is
by allergy avoidance and medication. Allergy avoidance can be by several ways.
Some of this methods are encasing mattresses and pillows in plastic covers, hot
wash bedding every 1-2 weeks, removing objects that accumulate dust, store
clothing in drawers, remove carpets or clean them regularly, using washable
curtains, removing cats or washing them weekly.
Medication
commonly used are topical corticosteroids, antihistamines and antileukotrienes.
Topical corticosteroids are the most effective in treatment of rhinitis. They
reduce inflammation and consequent hyperreactivity, reduce nasal and eye
symptoms and improve sense of smell. Antihistamines relieve running, itching
and sneezing but have little effect on blockage. Antileukotrienes are effective
against congestion and mucus production and are more superior when combined
with antihistamines. Decongestants are only used for a short period of time,
systemic steroids are used in severe disease and in combination with topical
steroids and nasal douching can also be done. Immunotherapy can also be used in
treatment.
Surgery may
be needed when there is marked septal deviation or bony turbinate enlargement
which makes topical nasal sprays usage difficult. The surgery will involve correcting
the deviation or reducing the turbinate enlargement and it is mostly done
endoscopically.
