Answer:
Possibility of cross allergic reaction
Step-by-step explanation:
In patients with a history of severe hypersensitivity reaction to penicillins, the use of Cephalosporins should be avoided. Given the chemical similarity of the classes, there is a possibility of cross allergic reaction.
Penicillin and cephalosporin are part of the same family of antibiotics (beta-lactams) and have a similar, but not equal, physical structure, where the two substances share the same R1 chain and the same beta-lactam ring chain.
When a history of severe allergy to IgE-mediated penicillin, such as anaphylaxis, is contraindicated the use of cephalosporin of any generation.