Vasculitis during immunotherapy treatment in a patient with allergy to Cupressus arizonica

Allergen immunotherapy dates back to 1911 and has been used successfully to treat large numbers of patients throughout the last century.

a 66-year-old woman presented with symptoms of allergic rhinitis and asthma due to sensitization to Cupressus arizonica. Specific immunotherapy was prescribed as a continuous 2-year treatment with a depot preparation of standarized and characterized allergen extracts of Cupressus arizonica pollen. Forty-eight hours after one maintenance dose of 0.8 cc, the patient presented palpable violaceous purpuric lesions and pruritus on both legs. We performed skin prick and intradermal tests with Cupressus arizonica. Twenty-four hours later, the 1/1 dilution intradermal skin test was positive. Biopsy showed leukocytoclastic vasculitis.

A middle-aged woman experienced cutaneous non-necrotizing vasculitis after 2 years of maintenance immunotherapy. The interval between injections and the first appearance of cutaneous lesions suggests a type III hypersensitivity immune reaction. Skin biopsy of the positive intradermal test also supports this hypothesis.