BACKGROUND: Alpha-Gal allergy is a delayed reaction to Galactose-alpha-1,3-galactose, triggered by the consumption of mammalian meat. Evidence implicates that a bite from a lone star tick is the cause for the development of the allergic response. Those who have Alpha-Gal allergy have to be extremely cautious about what they consume; an allergic reaction can be severe and life-threatening. Individuals living in the central and southern parts of the United States are most affected, corresponding to the distribution of the lone star tick. Because an increasing number of people in Arkansas have been vocal about suffering with this allergy, a legislative task force was formed to begin studying ways to promote awareness and encourage efforts to treat this condition. However, the epidemiology of Alpha-Gal allergy is not known as it is not currently reportable to any surveillance system.
METHODS: Laboratory results from January 2013-September 2015, provided by the only two laboratories that perform Alpha-Gal allergy testing, were examined. A total of 627 individual patients received IgE testing for Alpha-Gal allergy. Further testing to determine specific meat sensitivities was performed on a subset of 12 individuals. SAS (Version 9.3, Cary, NC, USA) was used to calculate simple descriptive statistics. Frequency tables were exported to Excel to visualize data.
RESULTS: The ages of those positive for Alpha-Gal allergy (271) ranged from 0 to 91 years, with the mean being 42.5 years. The proportion of those who tested positive for the allergy increased with age--the highest being among those who were 50 years and older (Χ2=15.2; p-value=0.034). Most of the positive samples were collected during the summer, suggesting that seasonality is related to incidence/testing (Χ2=13.7; p-value=0.003). A greater proportion of those who received testing and tested positive were female, though this difference was not significant. Most of the tests performed by one of the two labs were for individuals from northwest and central Arkansas. Two particular counties in northwest Arkansas accounted for the majority of the tests done, yet the proportion positive was less than 50% for both.
CONCLUSIONS: Limited laboratory data suggest that Alpha-Gal allergy in Arkansas affects mostly older (50+) female adults, with incidence/diagnosis occurring primarily during the summer.