Pre-diagnostic and non-advanced systemic mastocytosis without cutaneous involvement have an increased risk of anaphylaxis

Anaphylaxis is a relevant issue not only in acknowledged variants of SM, but also in pre-diagnostic forms. Idiopathic anaphylaxis may occur across different subtypes. Hymenoptera venom is the main trigger in indolent forms, whereas drug-induced reactions predominate in ISM and advanced SM, mainly through IgE-independent mechanisms. The risk of anaphylaxis is higher in pre-SM and ISM without cutaneous involvement, particularly in case of Hymenoptera venom sensitization. Our results highlight the need for allergological risk assessment and close monitoring especially in patients without skin lesions or with Hymenoptera venom sensitization.