Determination of the incidence of sensitization after penicillin skin testing.
BACKGROUND
Concerns for sensitization after penicillin skin testing are a factor in limiting the timing and population for whom this testing is offered. The sensitizing potential of the penicillin skin test has never been studied directly.


METHODS
A total of 329 volunteers underwent prick and intradermal skin testing with penicillin G, benzylpenicilloyl-polylysine, and a minor determinant mixture. Those with negative skin testing had repeat testing 4 weeks later. Medical history and antibiotic use were determined by interview, questionnaire, and electronic pharmacy records.


RESULTS
Seventy-two of the 329 subjects (22%) reported a history of previous beta-lactam reaction, of which 10 (14%) had a positive initial skin test. Overall, the initial skin test was positive in 23 of 329 (7%). Of the subjects with a negative initial skin test, 239 completed the second test 4 weeks later. Of these, 6 subjects (2.5%, 95% confidence interval 0.5% to 4.5%) converted to a positive skin test. None had taken a beta-lactam antibiotic between the two tests, and none had any previous history of beta-lactam reaction. One subject reported having never taken a beta-lactam antibiotic before. In comparison to the 233 subjects who did not convert their skin test, the statistically significant factors favoring sensitization were: female sex (odds ratio [OR] 6.53, P = 0.05), atopy (OR 5.31, P = 0.04), and history of food allergy (OR 6.35, P = 0.02). There was a trend toward more recent penicillin use in the newly sensitized subjects, but this was not statistically significant..


CONCLUSIONS
Penicillin skin testing may sensitize a small number of individuals to penicillin.
Nugent
Jeffrey S
JS
Wilford Hall Medical Center, San Antonio, Texas, USA. jeffrey.nugent@lackland.af.mil
Quinn
James M
JM
McGrath
Christianne M
CM
Hrncir
David E
DE
Boleman
William T
WT
Freeman
Theodore M
TM
D000328:Adult; D000900:Anti-Bacterial Agents / Q000009:adverse effects; D002511:Cephalosporins / Q000009:adverse effects; D003429:Cross Reactions; D004342:Drug Hypersensitivity / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D005512:Food Hypersensitivity / Q000150:complications; D006632:Histamine; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000150:complications; D007114:Immunization; D015994:Incidence; D007428:Intradermal Tests / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D010406:Penicillins / Q000009:adverse effects*; D012307:Risk Factors; D012882:Skin Tests / Q000009:adverse effects*
D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D010406:Penicillins; D006632:Histamine