Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 15 6 2017 12 30 547 550 EN Stefanie Aurich Department of Dermatology, Venereology and Allergology, University Hospital, Leipzig, Germany Anna-Theresa Seitz Department of Dermatology, Venereology and Allergology, University Hospital, Leipzig, Germany Janina Tomm Department of Dermatology, Venereology and Allergology, University Hospital, Leipzig, Germany AND Helmholtz Centre for Environmental Research, Leipzig, Germany Jan-Christoph Simon Department of Dermatology, Venereology and Allergology, University Hospital, Leipzig, Germany Regina Treudler Department of Dermatology, Venereology and Allergology, University Hospital, Leipzig, Germany 2016 01 05 2016 04 20 In medicine, patent blue violet (PBV) is utilized for staining lymphatic vessels in sentinel lymph node (SLN) surgery. Moreover, PBV (also called E131 ) is used as food additive. We report on a 51-year-old non-atopic female with early breast cancer, who was scheduled for SLN excision and experienced an intra-operative anaphylactic reaction. In diagnostics the skin prick test (SPT) was positive to PBV. Hypersensitivity reactions to PBV can arise after the first exposure in surgery as sensitization may arise from either PBV (E131) in foods (i.e. in sweets or blue curacao) or from other structurally closely related triarylmethane dyes in objects of everyday life like textiles, detergents, paints, cold remedies and cosmetics. This article supports the necessity of an increased awareness of the possibility of anaphylactic reactions to PBV during SLN surgery, even if the patient never had contact to PBV before. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/760 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/760/674