Cephalosporin allergic drug reactions

Hypersensitivity reactions Make careful inquiry for a history of hypersensitivity reactions. Monitor patients who have had immediate hypersensitivity reactions to penicillins or cephalosporins. If an allergic reaction occurs, discontinue the drug and institute supportive treatment. Cross-sensitivity with other penicillins or -lactam antibiotics is rare. 

In some patients, cephalosporins may cause an allergic reaction similar to the penicillin hypersensitivity described previously. A cross-sensitivity often exists a patient who is allergic to penicillin drugs will also display hypersensitivity to cephalosporin agents. Other principal adverse effects of cephalosporins include gastrointestinal problems such as stomach cramps, diarrhea, nausea, and vomiting. 

Allergic responses to drugs are mediated by the release of histamine or histamine-like substances, and they commonly present as skin rashes, particularly urticaria. More serious hypersensitivity responses include bronchospasm or the acute, explosive anaphylactic reaction with cyanosis and cardiovascular collapse. A delayed reaction known as serum sickness, although more often associated with such drugs as the penicillins and cephalosporins rather than with serum, manifests clinically 7 to 10 days after receiving the drug or serum as fever, malaise, joint pains, and urticarial skin rashes. 

De Week AL. Penicillins and cephalosporins. In Allergic Reactions to Drugs. Heidelberg Springer-Verlag, 1983 423. 

Hypersensitivity reactions (2% incidence) wide range, but rashes and drug fever most common, positive Coombs test, but rarely hemolysis. Assume complete cross-allergenicity between individual cephalosporins and partial cross-hypersensitivity with penicillins (about 5%). Most authorities recommend voiding (iTffl S()[ >1.cephalosporins in patients allergic to penicillins (tor gram-positive organism ... 

ADVERSE REACTIONS Hypersensitivity reactions are the most common side effects of cephalosporins they are identical to those caused by the penicillins, perhaps related to their shared /3-lactam structure. Patients who are allergic to one drug class may manifest cross-reactivity to a member of the other class. There is no skin test that can reliably predict whether a patient will manifest an allergic reaction to the cephalosporins. 

Each of the dmgs listed has activity against some gram-negative bacilli. All penicillins should be avoided in patients with a history of allergic reactions to any individual penicillin drug. Cephalosporins should also be avoided in patients who have had anaphylaxis or other severe hypersensitivity reactions following use of a penicillin. There is no cross-reactivity between the penicillins and aztreonam. The answer is (B). 

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