Prevalence of mastocytosis and Hymenoptera venom allergy in the United States.

BACKGROUND: Mastocytosis is a risk factor for Hymenoptera venom anaphylaxis (HVA). Current guidelines recommend measuring tryptase in patients with HVA and that those with mastocytosis pursue lifelong venom immunotherapy (VIT). Available data on HVA and mastocytosis largely derive from European single-center studies, and the prevalence of HVA with and without mastocytosis in the United States is unknown. OBJECTIVE: We sought to determine the prevalence of HVA and mastocytosis in the United States using an insurance claims database and evaluate the impact of mastocytosis on VIT in patients with HVA in a US cohort. METHODS: The IBM Watson Database, consisting of insurance claims from approximately 27 million US patients in 2018, was queried to identify patients with HVA and/or mastocytosis. Furthermore, a retrospective study of 161 patients undergoing VIT between 2015 and 2018 at the University of Michigan was conducted. RESULTS: In the IBM Watson Database, the prevalence of HVA was 167 per 100,000 (0.167%) and the prevalence of mastocytosis 10 per 100,000 (0.010%) overall and 97 per 100,000 (0.097%) among those with HVA. Mastocytosis showed a 9.7-fold increase among patients with HVA versus the general population. In the U-M cohort, 2.6% of patients with VIT had mastocytosis. Tryptase level did not correlate with venom reaction severity but was higher in patients with systemic VIT reactions. CONCLUSIONS: We observed a lower US HVA prevalence than previously reported. Mastocytosis was more common in US patients with HVA, though at lower rates than previously reported. In patients with VIT there was no correlation between tryptase level and reaction severity.

Safety of topical calcineurin inhibitors for the treatment of atopic dermatitis.

Atopic dermatitis is a chronic, highly pruritic, and frequently recurring inflammatory skin disease that can be burdensome to affected individuals as well as to their family members, the health care system, and society as a whole. Immunomodulatory agents, such as topical corticosteroids and topical calcineurin inhibitors (TCIs), target the underlying immunopathology of atopic dermatitis and are the foundation of pharmacologic treatment for disease exacerbations. Recent recommendations from the United States Food and Drug Administration prompted the addition of a black-box warning and medication guide for tacrolimus ointment and pimecrolimus cream (both TCIs). The recommendations were based on a theoretical risk of malignancy derived from safety profiles, animal data, and reported cases of malignancy from clinical trials and postmarketing safety surveillance of oral calcineurin inhibitors. We know of no data that suggest that TCI use increases the risk of malignancy. Several dermatologic associations have issued statements supporting the safety of TCIs, and independent oncology experts have concluded that reported lymphomas were not related to TCI use. The black-box warning added to the TCI prescribing information also states that no causal link has been established. Effective treatment of atopic dermatitis can help alleviate the burden this disease imposes, and TCIs remain important treatment options.