Allergen sensitisation in asthmatic children: consecutive case series.

OBJECTIVE

To investigate the pattern of sensitisation to aero-allergens and food allergens among asthmatic children in Hong Kong, and to investigate any correlation between atopy and the severity of asthma.

DESIGN

Consecutive case series.

SETTING

Paediatric out-patient clinic of a university teaching hospital, Hong Kong.

PARTICIPANTS

Two hundred and four consecutive children with physician-diagnosed asthma who attended from January 1999 through June 2000.

MAIN OUTCOME MEASURES: Demographic data, questionnaire assessment of asthma control, spirometric evaluation, response to skin prick testing, eosinophil count, and total serum immunoglobulin E concentration.

RESULTS

The median patient age was 8.2 years (range, 5.7-11.3 years), and the median 1-second forced expiratory volume was 95% of the predicted value. The median absolute eosinophil count in the peripheral blood was 0.48 x 10(9) /L and the ratio of total serum immunoglobulin E to the age-adjusted upper limit of the normal range was 2.7. Atopy, as defined by at least one positive response to skin prick testing, was found in 170 (83.3%) of the 204 patients. House dust mites were the most commonly sensitised aero-allergen (n=167; 81.9%). Sensitisation to food allergens was found in 47 (23.0%) of the patients. The self-reported frequency of asthmatic attacks was associated with a positive response to skin prick testing with animal allergens (P for trend = 0.001), whereas spirometric indices correlated with the degree of atopy and the presence of in vivo cockroach-specific immunoglobulin E.

CONCLUSION

Sensitisation to indoor aero-allergens, as determined by skin prick testing, is prevalent among Chinese children with mild-to-moderate asthma, whereas sensitisation to food allergens is not. The severity of asthma is correlated with skin prick test responses to pet and cockroach allergens.