Introduction

Seasonal allergic rhinitis or hay fever was called “catarrhus aestivus” (spring catarrh) in 19th century medical literature, but more recently has been labelled as a “post industrial revolution epidemic.”1 Its prevalence has increased in developed countries, particularly in the past two decades.2 One in six people is affected by allergic rhinitis.3 In 1990 the estimated cost of hay fever in the United States was $1.8 billion.4

Effective medication for this condition is available, and prophylactic treatment (topical corticosteroids, sodium cromoglycate) should be started two to three weeks before the pollen season to prevent priming by allergen. This year the warm spring has advanced the pollen season by two to three weeks and treatment should be started earlier. After concern over the risk of cardiac arrhythmias, the Medicines Control Agency is currently converting terfenadine, a commonly used antihistamine that is available over the counter, into a prescription only drug.

Methods

Most of the articles selected were from the personal library of GKS, who has 10 years of clinical and research experience in this subject. For an overview, we selected book chapters that had been written by leaders in the subject, while we selected individual papers for details of particular aspects of seasonal allergic rhinitis. Drug related details came from the British National Formulary, manufacturers' product data, and documents from the Medicines Control Agency.

Allergens

Seasonal allergic rhinitis is a type I immediate hypersensitivity reaction mediated by specific IgE antibody to a seasonal allergen, leading to mucosal inflammation characterised by sneezing, itching, rhinorrhoea, and nasal blockage. Pollens from wind pollinated grasses, trees, weeds, and spores from fungi are the commonest aeroallergens. Pollens are the male gametes of plants, and most antigenic pollens are 6-40 μm in diameter. Larger pollens from oil seed rape, which is pollinated by insects, have …