This system is one of a chronic allergic inflammation model. A single subcutaneous injection of antigens elicits a delayed-type response manifested by ear swelling. The entire response consists of three phases: Immediate, late, and chronic. The early-phase swelling peak within 1 h after allergen challenge is followed by the late-phase swelling 6-10 h late. Importantly, the ear swelling at the late-phase started on day2 and peak on day4. This late-phase ear swelling response is defined as IgE-mediated chronic allergic inflammation (IgE-CAI) and mainly regulated by basophils.