Features of in vivo diagnostics of delayed drug hypersensitivity to beta-lactams

Background. Beta-lactams are the most widely used group of antibacterial agents. They are used for treating of infectious complications of varying severity, including urgent situations. The exclusion of the entire beta-lactam group not only leads to a significant increase in the cost of treatment, length of hospitalization and the formation of resistance of the flora to alternative antibiotics, but also may be life threatening in some cases. Therefore, correct diagnosis and establishement of the offending medication can prevent the development of allergic reactions and to avoid unreasonable lifelong bans on the use of certain medications, which often lead to a decrease of the effectiveness of treatment and increase its cost. The aim of the study was to develop the diagnostic and management algorithm and of of patients with presumptive diagnosis of delayed drug hypersensitivity to beta-lactams. Materials and methods. A comprehensive in-depth examination, including in vivo tests with beta-lactams was done in 53 patients (37 - 70% women, and 16 - 30% men) with a presumptive diagnosis of delayed drug hypersensitivity to beta-lactams. The minimum age at the time of the reaction was 4 years, the maximum age was 86 years, the average age was 37 years,the median was 38,5 years old. The minimum age at the time of testing was 6 years, the maximum age was 89 years, the average age was 44 years, median was 44 years old. Results. In the group of patients with delayed drug hypersensitivity to beta-lactams (n=21) the diagnosis was confirmed by skin testing in 19 (90,5%) patients, in 18 (85,7%) to aminopenicillins, and 1 (4,8%) to ceftriaxone. In 2 (9,5%) cases, the diagnosis was established using a drug provocation test: for amoxicillin (4,8%) and for ceftriaxone (4,8%). According to the obtained data, the specificity of skin tests for the diagnostics of delayed drug hypersensitivity to beta-lactams was 100%. In case of delayed drug hypersensitivity to aminopenicillins, the sensitivity of skin tests was 94,7%, the negative predictive value of skin tests was 93,7%, the overall accuracy of skin testing was 97%, and the incidence of false-negative results was 5,3%. Conclusion. Skin testing is promising and safe in the diagnositics of delayed drug hypersensitivity to beta-lactams. It allows to exclude unreasonable contraindications for the use of beta-lactams, thereby increasing the effectiveness of treatment while reducing economic costs.