To further evaluate the accuracy of the penicilloyl-polylsine (PPL) skin test in detecting persons allergic to penicillin, this test was performed on 22 persons who had demonstrated hypersensitivity reactions to benzathine penicillin G (Bicillin) administered three months previously. Suitable control subjects were selected and skin tested with PPL. In the same subjects skin testing with penicillin G and a number of related molecules was also performed.
Twenty of 22 subjects with a history of clinical allergy to benzathine penicillin gave positive PPL skin tests, whereas only two of 40 control subjects reacted to the same antigen. Penicillin G, as well as other antigens tested, was considerably less effective in detecting the hypersensitive individual than was PPL.