Signs and Symptoms
An example of a delayed reaction would be maculopapular or morbilliform rashes associated with treatment with aminopenicillins, particularly ampicillin.
The incidence of rash associated with ampicillin has been estimated at 9.5%.
Since the rash typically appears 2-3 days or more after drug administration, it is thought to represent type IV (delayed) hypersensitivity.