ALLERGIC RHINITIS

Allergic disorders of the nose are very common in Southern Africa and affect almost 2 out of every 10 people. This allergic problem is often regarded as a rather trivial condition, but the truth is that the consequences of this illness may produce many untoward problems previously not adequately appreciated. The basis of nasal allergic problems results from the interaction of common inhaled allergens with specialised cells called mast cells in the nasal mucous membrane.

This reaction results in the release of powerful chemical agents of which histamine is the best known. These substances cause very severe swelling of the mucous membrane lining the nasal passages, intense itching and sneezing and the production of copious amounts of watery mucus. Allergic nasal disorders are divided into two main types; the seasonal form which is known as seasonal allergic rhinitis or more commonly as hay-fever, and secondly the year-round form known as perennial allergic rhinitis.

Most people, especially sufferers, are only too familiar with the symptoms of this allergic condition. It can include severe bouts of sneezing, intense itching of the nose and of the palate and even the ear canals. Profuse watery nasal mucus may stream from the nose, which often feels very blocked. Eyes may itch and tear and a common complaint is sensitivity to light. Sufferers are often irritable and develop frequent headaches. This may be due to the release of histamine into the blood stream following the allergic reaction.

Allergens which cause symptoms of seasonal allergic rhinitis are usually the pollens of grass, trees and a few weed species, all of which are wind-pollinated. It is only the small, light wind-borne pollens that cause the allergic reaction in the nose. Occasionally fungal spores are implicated, but as these usually have a year-round distribution, seasonal flare-ups are very unlikely. Certain tasks such as mowing the lawn during the pollen season will aggravate symptoms of hay-fever.

The diagnosis is readily apparent from the history, and skin tests are useful in identifying the allergens causing the symptoms. Treatment for hay-fever is divided into 4 main groups. It is impossible to avoid the allergens that cause this form of rhinitis, e.g. grass pollens, so medical treatment is unavoidable in most cases.

1. Anti-Histamines:

Recent developments in this field have seen the introduction of a new class of anti-histamines such as cetirizine (Zyrtec®), which no longer produce excessive drowsiness. In addition some of these new anti-histamines need only be taken once a day, which is a big advantage. The older sedating anti-histamines, especially those combined with oral decongestants such as pseudoephedrine, are no longer recommended.

2. Mast-Cell Stabilizers:

3. Steroid Sprays:

4. Hyposensitisation:

Patients with this condition often have a typical appearance known as the allergic facies. They are often pale with rather long, mournful faces, have dark rings under their eyes (the allergic shiners) and have dry lips due to mouth breathing. Many people have a clear line across the nose known as the allergic salute. Associated problems are very common and include abnormalities of the teeth and sinuses, ear problems and post-nasal drip.

The diagnosis is readily established on the history of the complaint, and skin prick tests or CAP RAST tests. The latter is done on a small sample of the patient’s blood and requires a laboratory to analyse results. In the majority of cases house-dust mites or cats or dogs are identified as the causative allergen. Treatment follows essentially the same lines as for hay fever, except that environmental control (i.e. avoidance of the allergen) is very useful, e.g. a careful mite control programme for the home.

2. Steroid nasal sprays are very useful in this condition and help enormously in relieving blockage of the nose by reducing the swelling of the nasal mucous membrane.

3. Hyposensitisation is not as effective as for pollen allergy, but will still be useful in more than 70% of house-dust mite sensitive patients.

In summary, most patients with nasal allergies can be effectively treated today and no one need suffer unnecessarily.