Hay fever. 2. Clinical features, diagnosis, investigation and treatment.

This is the second of two reviews of hay fever. The first article dealt with prevalence and natural history, historical background and mechanisms. This article outlines the clinical features of hay fever, examines the correlation of symptoms with pollen count and describes current views of diagnosis and investigation. History and examination, skin testing, the radio-immunosorbent test (RIST) and radio allergosorbent test (RAST) and the correlation between RAST and skin testing are described. Some consideration is given to the part played by nasal challenge tests and measurements of nasal airways resistance. The section on treatment includes some general considerations, avoidance measures, anti-histamines, nasal steroids, sodium cromoglycate, systemic steroids, nasal vasoconstrictors, hyposensitisation and eye preparations. The final section is centred on future developments.