Allergic Reactions to Local Anesthetics in Dental Patients: Analysis of Intracutaneous and Challenge Tests

Some dental patients have histories of adverse reactions to local anesthesia. The aim of the present study was to investigate the frequency of allergy to local anesthetics of dental patients who had histories of adverse reactions to local anesthesia based on the results of allergy tests in our institute over a period of 5 years. We investigated the past medical records of dental patients retrospectively, and twenty patients were studied. Three of the 20 showed a positive or false-positive reaction in the intracutaneous test, and one patient showed a false-positive reaction in the challenge test. Our results suggest that the frequency of allergy to local anesthetics is low even if patients have histories of adverse reactions to local anesthesia. However, allergy tests of local anesthetics should be performed in patients in whom it is uncertain whether they are allergic.

Evaluation of Western Blot CagA Seropositivity in Helicobacter pylori-Seropositive and -Seronegative Subjects

ABSTRACT CagA seropositivity is an important risk factor for gastric adenocarcinoma and duodenal ulcer. However, CagA seropositivity is also found in Helicobacter pylori-seronegative subjects. Is CagA seropositivity in these subjects a sign of a past H. pylori infection, or does it represent a false-positive reaction? This study investigates the intensity of the CagA immune reaction and the variation in CagA seroprevalence with year of birth for 650 subjects belonging to the Malmö Preventive Medicine cohort. CagA and H. pylori seroprevalences were determined by Western blot analysis (Helicoblot 2.1) and enzyme-linked immunosorbent assay. The peak intensity of the CagA band was significantly lower in H. pylori-seronegative subjects than in those with concomitant H. pylori seropositivity. In H. pylori-seropositive subjects, peak CagA intensity had a bimodal distribution. The prevalence of CagA-seropositive but H. pylori-seronegative subjects increased successively and significantly with year of birth, in contrast to the prevalence of CagA-seropositive and H. pylori-seropositive subjects, which decreased significantly. However, within H. pylori-seropositive and -seronegative subgroups, CagA seroprevalences were constant for different birth cohorts. If CagA seropositivity in H. pylori-seronegative subjects represents a past H. pylori infection, there must have been some mechanisms of eradication that were more common in younger subjects and that were of more importance than the presence of gastric atrophy and the longer duration and higher prevalence of H. pylori infection found in older subjects. Antibiotic treatment of H. pylori was not common practice at the time of enrollment. On the other hand, a false-positive reaction would be constant and independent of birth cohorts, as with the H. pylori-seronegative subgroup of our study. Peak CagA intensity in H. pylori-seronegative subjects corresponded to the lower part of the bimodal distribution of peak CagA intensity in H. pylori-seropositive subjects. We conclude that a major proportion of CagA seropositivity in H. pylori-seronegative subjects represents a false-positive reaction. Peak CagA intensity has a bimodal distribution in H. pylori-seropositive subjects. Low-intensity CagA seropositivity in H. pylori-seropositive subjects is indeterminate, representing both false-positive and true-positive reactions.