Safety of ultra-rush schedule of subcutaneous allergen immunotherapy with house dust mite extract conducted in an outpatient clinic in patients with atopic dermatitis and allergic rhinitis

Abstract

Purpose: Ultra-rush schedule of subcutaneous allergen immunotherapy (UR-SCIT) administering maximum maintenance dose of allergen extract within one day can save time and effort for allergen immunotherapy in patients with allergic disease. However, UR-SCIT is associated with an increased risk of systemic reaction (SR) and typically has been conducted in a hospital admission setting. To overcome disadvantages of UR-SCIT, we evaluated the safety of UR-SCIT conducted in an outpatient clinic in patients with atopic dermatitis (AD) and allergic rhinitis (AR). Methods: UR-SCIT was performed in 538 patients with AD and/or AR sensitized to house dust mite (HDM). A maximum maintenance dose of tyrosine-adsorbed HDM extract (1 mL of maintenance concentration) was divided into 4 increasing doses (0.1, 0.2, 0.3, and 0.4 mL) and administered to the patients by subcutaneous injection at 2-hour intervals for 8 hours in an outpatient clinic. SRs associated with UR-SCIT were classified according to the World Allergy Organization grading system. Results: SR was observed in 12 of 538 patients (2.2%) with AD and/or AR during UR-SCIT. The severity grades of the observed SRs were mild-to-moderate (grade 1 in 7 patients, grade 2 in 4 patients, and grade 3 in 1 patient). The scheduled 4 increasing doses of HDM extract could be administered in 535 of 538 patients (99.4%) except 3 patients who experienced SR before administration of the last scheduled dose. SR was observed within 2 hours in 11 patients after administration of the scheduled doses of HDM extract except one patient who experienced a grade 2 SR at 5.5 hours after administration of the last scheduled dose. Conclusions: UR-SCIT with tyrosine-adsorbed HDM extract conducted in an outpatient clinic was tolerable in patients with AD and AR. UR-SCIT can be a useful method to start a SCIT in patients with AD and AR.