Early sensitization to house dust mite is a major risk factor for subsequent development of bronchial asthma in Japanese infants with atopic dermatitis: results of a 4-year followup study

Background: Bronchial asthma (BA) often develops in children with atopic dermatitis (AD). Identification of factors that could predict the development of asthma in children with AD is useful for early intervention. Objective: We undertook a 4-year followup study to clarify the factors involved in the development of BA in infants with AD. Methods: We registered 169 infants with AD who were free of BA at registration and examined the prevalence and characteristics of the subsequent development of BA among these patients. Results: Among the patients followed for 4 years, approximately 45% experienced asthma-like respiratory symptoms, and 35% were diagnosed as asthmatic patients by pediatric allergologists. Patients who developed BA showed early appearance of house dust mite (HDM)-specific immunoglobulin E (IgE) and persistently high levels of food-specific IgE. Male sex, a positive family history of BA, and the appearance of HDM-specific IgE were identified as significant risk factors for the early development of BA, but the significance of these parameters decreased thereafter. A positive family history of AD, the outcome of skin lesions, and keeping furred pets were also identified as risk factors in a part of the followup period. Among the parameters examined, the early appearance of HDM-specific IgE was the most significant risk factor. Conclusion: Appearance of HDM-specific IgE antibodies in early childhood, which seems to be mainly influenced by genetic factors, is a major risk factor for the subsequent development of BA in children with AD, but the influence decreases after longer followup.