Penicillins allergy delayed-type hypersensitivity reactions

If a patient has a mild, delayed allergy to penicillin, first-generation cephalosporins are effective alternatives but should be avoided in patients with an immediate-type hypersensitivity reaction. 

If a patient has a mild, delayed allergy to penicillin, first-generation cephalosporins (such as cefazolin) are effective alternatives, but they should be avoided in patients with a history of immediate-type hypersensitivity reactions to penicillins (see Table 109-6). The potential for a true immediate-type allergy should be assessed carefully, and a penicillin skin test should be conducted before giving antibiotic treatment to any patient claiming an allergy. 

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