A 10-year retrospective study on benzocaine allergy in the United Kingdom.
BACKGROUND
Benzocaine has been labeled a notorious sensitizer. It is thought to be a common and potent sensitizer. It is suggested that such patients should routinely avoid tetracaine and procaine, as cross-reactions between benzocaine and such caines occurred commonly. Benzocaine also currently remains the screening chemical on the European Standard Battery (ESB) for topical caine allergy.


OBJECTIVE
To identify the rate of incidence of benzocaine allergy in the United Kingdom, and the level of cross reactivity between other caines in the ESB.


METHODS
The results from a 10-year retrospective study of 5,464 patients, subjected to patch testing with a modified ESB, which included caine mix III (Chemotechnique Diagnostics, Tygelsjo, Sweden), and the results of caine mix IV (Chemotechnique) reactions in 265 of these patients who complained of anogenital symptoms, are discussed.


RESULTS
Majority of allergic reactions occurred with the constituents of caine mix III, with benzocaine reactions being the least common allergen in this group. Cross reactivity between benzocaine and other caines, occurred infrequently.


CONCLUSIONS
Our data indicate that benzocaine allergy is not common in the United Kingdom. As cross-reactivity between benzocaine and other caines did not occur commonly, a significant number of relevant allergic reactions to other caines may go undetected, as benzocaine remains the screening chemical for topical anaesthetic allergy on the ESB. We suggest benzocaine be removed from the ESB, and be replaced by caine mix III.
Sidhu
S K
SK
Department of Environmental and Contact Dermatitis, Amersham Hospital, Buckinghamshire, United Kingdom.
Shaw
S
S
Wilkinson
J D
JD
D000779:Anesthetics, Local / Q000009:adverse effects*; D001566:Benzocaine / Q000009:adverse effects*; D004342:Drug Hypersensitivity / Q000453:epidemiology* / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D010328:Patch Tests; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D006113:United Kingdom / Q000453:epidemiology
D000779:Anesthetics, Local; D001566:Benzocaine