Approach to antibiotic selection in patients with a history of penicillin allergy. aIt is often difficult to obtain an accurate history; if in doubt, assume that reaction could have been an urticarial rash. bAvoid use of first-generation cephalosporins. Stevens-Johnson syndrome and toxic epidermal necrolysis are not IgE mediated. If the suspected drug reaction was either of these, then avoid skin testing and use of penicillins. cSkin testing with amoxicillin is sometimes used if the reaction was to amoxicillin, but the incidence of false negatives is unknown. dIf the reaction was serious, then one may challenge in a supervised setting using a 'graded challenge' with escalating oral doses followed by intravenous administration, if applicable. Reprinted with permission . Copyright © 2002 the Infectious Diseases Society of America.