“…The common occurrence of other atopic diseases, in particular asthma, in penicillin allergies (25, 37, 83, 87) and of penicillin allergy in patients with atopic diseases (4,20,26,50) may be due to a genetic relationship between penicillin 12O allerfj;y and the atopic diseases. However, other factors may also cause a common occui'rence of atopic chsease and penicillin allergy in the same patient: (i) Selection, wholly or partially, of penicillin allergies among atopie patients in a specialized division for allergic diseases, (2) increased exposure to penicillin in patients having other allergic diseases, in particular bronchial asthma with a tendency to infection, and thereby an increased possibility of sensiti/.ation.…”