Positive patch test reactions to gentamicin show sensitization to aminoglycosides from topical therapies, bone cements, and from systemic medication.

BACKGROUND

A history of prolonged use of topical antimicrobials is common among patients with positive patch test reactions to gentamicin and to aminoglycosides.

OBJECTIVES

The aim of this study was to show sources of gentamicin sensitization in patients with positive patch test reactions to gentamicin.

PATIENTS AND METHODS

About 7814 patients were patch tested with a baseline patch test series and 620 of them were further tested with gentamicin. The clinical histories, concurrent contact sensitivities, and sources of sensitization are analysed among these patients.

RESULTS

Positive patch test reactions to gentamicin were seen in 29/620 patients, most of whom (18/29) also reacted to neomycin and to kanamycin (7/29). Mean age of the gentamicin-positive patients was 62 years, but three young operating room nurses with hand dermatitis had a history of gentamicin exposure from bone cement. Among the 11/29 neomycin-negative patients, a history of exposure to different aminoglycosides was apparent, and one patient had a history of systemic netilmicin-medication-associated exanthema.

CONCLUSIONS

Positive patch test reactions to gentamicin reflect sensitization to different aminoglycosides for which gentamicin seems to represent a sensitive indicator. Gentamicin sensitization may result from occupational exposure to gentamicin containing bone cements or from systemic medication with aminoglycosides.