Since racial differences in skin immunology can impact histamine control skin test results, we investigated whether racial ethnicity plays a role in influencing the reaction in IgE-mediated skin testing.

We performed a retrospective chart review (from 1994-2003) of 2414 patients presenting at a New York City Allergy Clinic. The data included race (African-American, Hispanic-American, Asian-American, or Caucasian), drugs used before the skin test, and skin test results, including histamine control response. These values were used to calculate mean ranks (MR) by patient characteristics, which were compared using the Kruskal-Wallis test, a non-parametric comparison of independent groups.

Histamine reactions were: 1+: 1.4%, 2+: 14.2%; 3+: 60.8%; 4+ 23.5%. African-Americans (n=1404) had significantly higher reaction (p<0.01), whereas Hispanics (n=1210), Asians (n=1189) and Caucasians (n=1186) were not substantially different.

Asian-Americans did not have a statistically significant difference in histamine skin test control reaction, when compared with Hispanic-Americans and Caucasians. In contrast, African-Americans had a higher reaction than the other racial groups. These racial differences may be related to skin pigmentation, socio-economic factors, or genetics.