Dermatitis Due to the Procaine Fraction of Procaine Penicillin1

In view of the not infrequent occurrence of allergic skin reactions from the ingestion, injection, inhalation and topical application of procaine penicillin, it is important to know whether it is the penicillin or the procaine part of the molecule or whether it is the whole molecule which produces the eruption. While many investigators have reported on allergic skin sensitization to penicillin as proven by clinical events, patch tests, and intracutaneous tests, there are only two reports, by Peck and Feldman (1) and by Kile (2), which deal with cases of hypersensitivity to the procaine part of the procaine-penicillin molecule. In addition, the report by Berke and Obermayer (3) shows that some subjects develop a sensitivity to both penicillin and procaine.