Demographics, Types of Patient-Reported Allergic Diseases, and Anaphylaxis in Mastocytosis: A Single-Center US Experience.

BACKGROUND

Patients with mastocytosis are at increased risk of anaphylaxis. Idiopathic anaphylaxis and venom-induced allergy are commonly reported in mastocytosis; however, the incidence of other allergies has been less well studied.

OBJECTIVE

To characterize the true prevalence of allergic disease including food, venom, contrast, and drug allergy compared with the number of patients who simply avoid potential triggers. We also gathered demographic information.

METHODS

We performed a retrospective study of 259 consecutive pediatric and adult patients with a confirmed diagnosis of either cutaneous or systemic mastocytosis who received care through the University of Michigan Health system from January 1, 2018, to March 17, 2021.

RESULTS

Mastocytosis was more prevalent in non-Hispanic white population. As compared with the general population, patients had similar rates of atopy and allergies with a slight increase in reported asthma prevalence. The overall prevalence of anaphylaxis was 28%, and the great majority occurred in systemic mastocytosis, with the most common trigger being hymenoptera venoms. Most patients reported drug allergies preemptively to avoid exposure, particularly to nonsteroidal anti-inflammatory drugs. We also saw an increase in contrast-induced anaphylaxis compared with previous literature, and a lower prevalence of venom allergy as compared with European cohorts.

CONCLUSIONS

Our study characterizes the rate of common atopic conditions as well as allergies in a large cohort of patients with mastocytosis in the United States. Anaphylaxis in cutaneous mastocytosis is rare. Hymenoptera venoms were the most common trigger for anaphylaxis, whereas drug allergies were overreported preemptively to avoid potential exposures due to concern for having a reaction.