The investigators are conducting a prospective study to determine the safety and outcomes of
placebo-controlled graded drug challenges without prior skin testing in patients with a
low-risk history of antibiotic hypersensitivity reaction based on history alone. The
investigators hypothesize that the rate of reaction to graded drug challenges without prior
skin testing in patients with a low-risk history of drug hypersensitivity reaction based on
history alone will not be meaningfully more than the rate of reaction to placebo. The
investigators hypothesize that the rate of adverse reactions to drug challenges without prior
skin testing will not be meaningfully more than the rate of adverse reactions with prior skin
testing as was observed in the investigators' historical clinic cohort.