Effectiveness and safety of subcutaneous immunotherapy with standardized house dust mite extract for patients under the age of 5 years : A prospective cohort study

Dear Editor, Standardized house dust mite (HDM) allergen extracts are available in Japan for patients requiring subcutaneous immunotherapy (SCIT), however, HDM SCIT for patients aged under 5 years has not been recommended due to the lack of administration experience. To the best of our knowledge, this is the first prospective cohort study to examine the effectiveness and safety of HDM SCIT for patients aged under 5 years. Patients with allergic rhinitis and/or bronchial asthma, who had specific IgE antibody against Dermatophagoides, were included in this study. Rush induction of HDM SCIT (HDM rSCIT) was introduced in 17 patients aged under 5 years (younger group) and 45 patients aged 5 years and above (older group); the treatment was maintained for one year in both the groups. The patients were hospitalized during HDM rSCIT and administered 500 Japanese allergy units (JAU) of HDM once a month in the outpatient clinic during the maintenance phase (Supplementary Table 1). In patients who developed a systemic reaction (SR) during HDM rSCIT, the dose was increased to 500 JAU using the conventional method.