Citrus red mite (Panonychus citri) is a common sensitizing allergen among children living around citrus orchards.

Abstract

BACKGROUND: A recent investigation has suggested that Panonychus citri (citrus red mite) is the most common causative allergen in citrus-cultivating farmers with asthma or allergic rhinitis.

OBJECTIVE: A cross-sectional survey was performed to evaluate the prevalence of asthma and sensitization to P. citri among children living around citrus orchards.

METHODS: A total of 1,055 children living around citrus orchards were enrolled. There were 544 boys and 511 girls with a mean age of 12.3 (range 7 to 16) years. They were evaluated by the ISAAC questionnaire, and a skin prick test with 13 common aeroallergens including P. citri and Japanese cedar pollen. Children who recorded ever having experienced wheezing on the questionnaire were evaluated by methacholine bronchial provocation test and determined to have asthma if they showed bronchial hyperresponsiveness to methacholine simultaneously.

RESULTS: The positive skin test response to one or more inhalant allergens except P. citri was 35.5%, but when including P. citri, the positive response increased to 37.7%. The most common sensitizing allergens in the order of decreasing frequency were Dermatophagoides pteronyssinus (26.6%), D. farinae (22.7%), P. citri (14.2%), cockroach (11.3%), and Japanese cedar pollen (9.7%). Among the children without sensitization to house dust mites, the sensitization rate to P. citri was significantly higher in those 13 and over than in those under 12 (5.8% versus 2.5%, P < .05). The prevalence of asthma was not different between the children with sensitization to P. citri and those without it (5.4% versus 4.0%, P > .05), although the prevalence was higher in those with sensitization to D. pteronyssinus or D. farinae than in those without sensitization to these allergens (7.9% versus 2.9%, P < .05; 9.7% versus 2.6%, P < .05).

CONCLUSION: Citrus red mite is a common sensitizing allergen among children living around citrus orchards. The features of sensitization and development of asthma are different between citrus red mite and house dust mites.