Ampicillin-specific rashes
B. B. Adcock and D. P. Rodman
Department of Family Medicine, University of Alabama School of Medicine at Tuscaloosa, USA.
Ampicillin is one of the most common drugs to elicit a rash, with an
overall incidence of 3% to 8%. "Ampicillin-specific" rashes are thought to
be nonhypersensitivity reactions and cause maculopapular erythema with
minimal irritation or pruritus. If the rash is indeed an
ampicillin-specific one, then discontinuation of ampicillin is not
mandatory, and subsequent use of ampicillin or other beta-lactam
antibiotics is tolerated. On the other hand, true hypersensitivity
reactions with urticarial and anaphylactic properties demand prompt
discontinuation of the drug and warrant supportive care. Unfortunately,
there is no immediate definitive scientific method to differentiate between
the two.
