The Association of Skin Test Reactivity, Total Serum IgE Levels, and Peripheral Blood Eosinophilia with Asthma in Kuwait

There is evidence that elevated serum immunoglobulin E (IgE) and eosinophilia correlate well with allergic skin test reactivity. These parameters have been used as alternative methods to characterize atopic subjects. Skin test reactivity is the only measure used routinely in clinical practice in Kuwait to reflect atopy in asthma patients. This study examines the usefulness of the two other parameters of atopy in patients with asthma, and to determine the most common allergens involved in Kuwait. Between 1998 and 1999, 101 asthma patients and 33 healthy controls were recruited for this study. Skin sensitivity test, serum total and specific IgE, total blood eosinophil count (B-EOS), and eosinophil cationic protein (ECP) tests were performed in patients and controls. Nine allergens known to be prevalent in this environment were selected for the skin test and specific IgE test. Spirometry was also measured. These parameters were repeated after 4 weeks of therapy in the patients only. Skin test reaction was positive in 81% of the patients, while total IgE above 200 kU/L was obtained in 63% of cases. B-EOS above 300 ± 10³/L was found in 75% of cases. House dust mite reactivity (positivity) was the most frequently encountered skin allergy, occurring in 28% of the patients. IgE correlated positively with B-EOS and ECP. B-EOS similarly correlated positively with ECP. There was a negative correlation between ECP and forced expiratory volume in 1 sec (FEV₁) (% predicted) as expected. At least one positive parameter of atopy was found in 95% of the patients. In 48% of the patients, all three parameters of atopy were found to be positive. Skin test reactivity and elevated IgE were found together in 62% of the cases. This study reveals a significant degree of allergy among patients with asthma in this environment. Skin testing was found to be the most effective measure of atopy in this environment, and correlates well with the other more sensitive newer tests.