Wednesday, 19 August 2020

Allergic Rhinitis

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.

one year ago