Survey of asthmatic patients' sensitization to house dust mites in southwestern Taiwan

Background: House dust mites (HDM) are one of the major risk factors for the development of bronchial asthma. The percentage of sensitization to HDM was reported to be 71.9% in Taipei City. In southwestern Taiwan, the percentage of sensitization to HDM has not been estimated. We retrospectively reviewed the medical records of asthmatic patients treated at the Chiayi branch of Chang Gung Memorial Hospital to investigate the percentage and associations with demographic characteristics. Methods: We analyzed the data of 194 asthmatic patients diagnosed between January 2003 and July 2005. Sensitization to indoor allergens was identified by serum specific immunoglobulin E (IgE) of ImmunoCAP. Demographic characteristics of age, gender and residence were evaluated for associations with allergic sensitization. Results: The percentage of sensitization to HDM was only 45.9% in patients in southwestern Taiwan. The majority of the studied group were elderly patients. The age variable significantly influenced the percentage of sensitization to HDM and cockroaches (p < 0.001 in both comparisons). The gender variable contributed to sensitization to cockroaches only (p = 0.002). For residential variables, there was no significant difference in the percentage of allergic sensitization to all tested indoor allergens among distinct areas of southwestern Taiwan. Conclusion: The percentage of sensitization to HDM in asthmatic patients residing in southwestern Taiwan was lower than that in metropolitan patients. This discrepancy might be attributed to the larger proportion of aged patients.