Patent blue V dye (PBV) is frequently used as a perioperative drug for lymphangiography, as well as a food additive. Hypersensitivity to PBV is poorly documented in adults and had not been previously described in children. The diagnosis of PBV allergy depends on corroboration of history consistent with an IgE-mediated reaction and confirmatory skin tests. We present in this paper a paediatric case of PBV anaphylaxis and of biphasic reaction that exemplifies the challenges involved in diagnosing and managing this rare but potentially life-threatening allergic reaction.

BACKGROUND: It is not established whether the risk of anaphylaxis induced by peanuts or tree nuts in children increases at specific times of the year. We aimed to evaluate the risk of peanutand tree-nut-induced anaphylaxis during certain cultural holidays in Canadian children. METHODS: We collected data on confirmed pediatric cases of anaphylaxis presenting to emergency departments in 4 Canadian provinces as part of the Cross-Canada Anaphylaxis Registry. We assessed the mean number of cases per day and incidence rate ratio (IRR) of anaphylaxis induced by unknown nuts, peanuts and tree nuts presenting during INTERPRETATION: We found an increased risk of anaphylaxis induced by unknown nuts and peanuts during Halloween and Easter among Canadian children. Educational tools are needed to increase awareness and vigilance in order to decrease the risk of anaphylaxis induced by peanuts and tree nuts in children during these holidays.