Prevalence and impact of past history of food allergy in atopic dermatitis.

BACKGROUND

Increases in allergic diseases have been reported from various epidemiological surveys. However, a few reports demonstrate the comorbidity of food allergy (FA) and allergic march. The aim of this study was to assess the prevalence and comorbidity of allergic diseases in Japanese students.

METHODS

First-year students (n = 3,321; 2,209 male and 1,112 female) at Osaka University were asked about allergic diseases using postal interview sheets. Personal and family histories of doctor-diagnosed allergic diseases, clinical courses, and aggravating factors were included in the questionnaires.

RESULTS

The lifetime prevalence of allergic rhinitis (AR), atopic dermatitis (AD), bronchial asthma (BA), and FA was 35.7%, 16.5%, 9.9%, and 7.0%, respectively. Disease-specific family histories existed for AR, AD, and BA. There was a positive correlation between the number of family histories of allergic disease and comorbidity (R = 0.370, P < 0.001). Comorbidity with AD significantly lowered the onset age of both BA (P = 0.010) and AR (P < 0.001). In addition, the onset age of AD was remarkably lowered by comorbidity with FA (P < 0.001). Comorbidity with FA was the highest risk factor for the progression of allergic march. Although most students showed improvement in AD, BA, and AR over time, the peak recurrence period was observed in adolescence.

CONCLUSIONS

These findings indicate that AD associated with FA accelerates the subsequent progression of allergic march. Early appropriate management for genetically high-risk groups is important for the prevention of allergic march.