Twenty-nine patients with histories of allergy to penicillin required therapy with penicillin for severe infections. Three had had anaphylaxis; 12, exanthems late in onset; 8, urticaria; and nine had a variety of other cutaneous manifestations. One had a history of eosinophilia following penicillin therapy. All 29 had negative immediate skin tests; none developed immediate urticarial adverse reactions following reinstitution of penicillin therapy. However, five developed generalized maculopapular eruptions within 24 hours to 21 days after initiation of therapy. Indications for treatment with penicillins were subacute bacterial endocarditis (five), septicemia (two), pneumonia (two), rheumatic heart disease (three), and a variety of other infectious diseases including syphilis, osteomyelitis, and gas gangrene. The results indicate that a history of allergy to penicillin is not as reliable as skin testing with haptenes derived from penicillin to predict whether an immediate adverse effect is likely to ensue.
Fellner MJ, Weidman AI, Klaus MV, Baer RL. The Usefulness of Immediate Skin Tests to Haptenes Derived From PenicillinA Study in Patients With a History of Previous Adverse Reactions to Penicillin. Arch Dermatol. 1971;103(4):371-374. doi:10.1001/archderm.1971.04000160021004