Allergen skin test and total IgE in adults with rhinitis in Singapore

The aim of this study was to determine the allergen skin test positivity and total serum IgE of adult patients in Singapore with clinical features suggestive of allergic rhinitis. The study was carried out prospectively from January to August 1990. All patients had one or more of three symptoms (1) rhinorrhoea or nasal congestion, (2) itching nose or throat and (3) sneezing, as well as pale edematous nasal mucosa. Twenty inhalant allergens (Greers Laboratory, USA) were used for skin prick test (SPT). Serum total IgE was measured using 3M FAST test. Eighty-five consecutive patients, 54 males and 31 females, were studied. Their mean age (SD) was 26.8 (6.1) years. More than half (55.3%) had severe symptoms affecting work. Twenty percent did not have any positive skin reaction compared with 44.9% of age-matched healthy controls; 62.4% had 2 or more positive reactions compared to only 37.2% of controls. These differences were statistically significant (p < 0.002). The two most commonly, positive allergens were Dermatophagoides farinae (76.5%) and house dust (61.2%). No significant difference was found in the skin test positivity between males and females. Forty-three patients also had serum total IgE measurement and their geometric mean IgE was 240 IU/I which was significantly higher than the geometric mean IgE of healthy controls (88 IU/I, P = 0.0005).