BACKGROUND: Alpha-gal syndrome (AGS) is an IgE-mediated allergy to galactose-alpha-1,3-galactose. Clinical presentation ranges from hives to anaphylaxis; episodes typically occur 2-6 hours after exposure to alpha-gal-containing products. In the United States, lone star tick bites are associated with development of AGS. To characterize features of AGS, we evaluated a cohort of patients presenting for care at the University of North Carolina, focusing on symptoms, severity, and identifying features unique to specific alpha-gal-containing product exposures. METHODS: We performed a chart review and descriptive analysis of 100 randomly selected patients with AGS during 2010-2019. RESULTS: Median age at onset was 53years, 56% were female, 95% reported White race, 86% reported a history of tick bite, and 75% met criteria for anaphylaxis based on involvement of 2 organ systems. Those reporting dairy reactions were significantly less likely to report isolated mucocutaneous symptoms (3% vs 24%; ratio [95% CI]: 0.1 [0.1, 0.3]) than those who tolerated dairy, and were more likely to report gastrointestinal symptoms (79% vs 59%; ratio [95% CI]: 1.3 [0.7, 2.6]), although this difference was not statistically significant. Dairy-tolerant patients demonstrated higher alpha-gal sIgE titers (as a percentage of total IgE) than dairy-reactive patients (GM 4.1[95% CI: 2.7, 6.1] vs. GM 2.5 [95% CI: 1.3, 4.8], respectively; ratio - 1.6 [95% CI: -1.0, 3.9]). CONCLUSION: While tick exposure is common in the southern United States, nearly all AGS patients reported a tick bite. Gastrointestinal symptoms were prominent among those reporting reactions to dairy. Anaphylaxis was common, underscoring the severity and need to raise awareness of AGS among patients and providers.

From 2016 through 2017, unprecedented increases in all nationally notifiable tickborne diseases were reported to the Centers for Disease Control and Prevention (CDC). The largest percentage increase was seen in reported cases of spotted fever rickettsiosis (SFR): a 46% increase from 4269 cases to a record 6248.1 Increases were reported in both new areas and in known endemic states. Although the New England, East North Central, and Middle Atlantic regions typically report only a handful of cases each year, in 2017, these areas experienced, a 215%, 78%, and 65% increase in reported cases, respectively. Among tickborne diseases, only anaplasmosis, with a 39% increase during this time, approached the rise seen with SFR. Although this increase raises concerns for elevated disease risk, additional factors are likely contributing to the high number of reports.