Allergic rhinitis and its management
Allergic rhinitis (commonly known as 'hay fever', althoughit is not related to hay and there is no fever) is a condition characterized by rhinorrhoea, nasal obstruction, sneezing,conjunctivitis, lacrimation, and nasal and pharyngeal itching. It is usually seasonal, with tree pollens being theallergen in the spring months and grass pollen in the summer. A perennial form occurs in those patients sensitiveto allergens such as house dust, which are in the air allyear round.
Food allergy is an often quoted but clinicallyrare cause of rhinitis.Pathologically the mucosa of the nose is oedematousand inflamed, and the secretions are rich in eosinophils.Nasal polyps and sinus infection may be present, especiallyin the perennial type. The conjunctivae are congested andoedematous.
The diagnosis is made by taking a carefulhistory. Skinprick testing for a battery of common allergensis helpful. Serum IgE is usually elevated, and occasionallya radioallergoimmunosorbent test will help to define theallergen. The major differential diagnosis is from vasomotorrhinitis, which is a similar syndrome but with nodocumented allergic basis. Other conditions that maypresent in a similar fashion include exposure to irritantsand repeated upper respiratory tract infections.
Management
Although the symptoms of allergic rhinitis tend to improveas the subject gets older, they can, when active, be severe.Most of the relevant allergens are ubiquitous and thereforeunavoidable. The first line of treatment is topical:nasal sprays or drops containing corticosteroids, such asbeclometasone or budesonide, or disodium cromoglycate,are useful when used on a regular basis. Disodium cromoglycateeyedrops are also helpful for the conjunctivitis.
These drugs can be supplemented by a non-sedating antihistamineby mouth, such as loratadine and fexofenadineor astemizole. The place of hyposensitization is debatable,and is usually reserved for isolated grass pollen allergy.Hyposensitization can be complicated by anaphylacticshock and should only be undertaken where resuscitationfacilities are available. Occasionally a small dose of oralcorticosteroids, e.g. prednisolone (10-15mg/day), or one ortwo injections of a depot corticosteroid during the seasonmay be necessary.
Food allergy is an often quoted but clinicallyrare cause of rhinitis.Pathologically the mucosa of the nose is oedematousand inflamed, and the secretions are rich in eosinophils.Nasal polyps and sinus infection may be present, especiallyin the perennial type. The conjunctivae are congested andoedematous.
The diagnosis is made by taking a carefulhistory. Skinprick testing for a battery of common allergensis helpful. Serum IgE is usually elevated, and occasionallya radioallergoimmunosorbent test will help to define theallergen. The major differential diagnosis is from vasomotorrhinitis, which is a similar syndrome but with nodocumented allergic basis. Other conditions that maypresent in a similar fashion include exposure to irritantsand repeated upper respiratory tract infections.
Management
Although the symptoms of allergic rhinitis tend to improveas the subject gets older, they can, when active, be severe.Most of the relevant allergens are ubiquitous and thereforeunavoidable. The first line of treatment is topical:nasal sprays or drops containing corticosteroids, such asbeclometasone or budesonide, or disodium cromoglycate,are useful when used on a regular basis. Disodium cromoglycateeyedrops are also helpful for the conjunctivitis.
These drugs can be supplemented by a non-sedating antihistamineby mouth, such as loratadine and fexofenadineor astemizole. The place of hyposensitization is debatable,and is usually reserved for isolated grass pollen allergy.Hyposensitization can be complicated by anaphylacticshock and should only be undertaken where resuscitationfacilities are available. Occasionally a small dose of oralcorticosteroids, e.g. prednisolone (10-15mg/day), or one ortwo injections of a depot corticosteroid during the seasonmay be necessary.
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