We have evaluated hundreds of patients with a history of reactions to penicillin(s) (penicillin, amoxicillin, or related cephalosporins). After evaluation and testing, more than 90% of these patients can safely take these drugs without fear of a severe allergic reaction.
The testing occurs in two phases, skin testing and an oral challenge. We first inject a small amount of the drug under the skin with a sterile needle and look for a mosquito bite-like reaction in 15 minutes. This is called intradermal testing. If this is negative a series of three oral doses of penicillin or related antibiotic will be given 20 minutes apart.
A positive response to any of the tests warrants stopping the testing and you are then considered to be allergic to penicillin. If all tests are well tolerated, you are no longer considered allergic and may receive penicillin and related antibiotics without restriction. The skin testing and oral challenge will take approximately two hours.