Cephalosporins skin reactions with

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. 

The cephalosporins are contraindicated in patients with known allergies or intolerances to any of the cephalosporins. Because the penicillins and cephalosporins have a common chemical structure, cross-allergies occur with these drugs. Thus before initiating therapy with a cephalosporin, careful inquiry should be made concerning previous hypersensitivity reactions to the other drugs. Because a secondary vitamin K deficiency can develop with cephalosporin use, the cephalosporins are contraindicated in patients with hemophilia. Cefaclor is also contraindicated in any patient with previous drug-related joint and skin reactions. 

Allergy Cephalosporins cause a range of allergic reactions from skin rashes to anaphylactic shock. These reactions occur less frequently with cephalosporins than with penicillins. Complete cross-hypersensitivity between different cephalosporins should be assumed. Cross-reactivity between penicillins and cephalosporins is incomplete (5-10%), so penicillin-allergic patients are sometimes treated successfully with a cephalosporin. However, patients with a history of anaphylaxis to penicillins should not be treated with a cephalosporin. 

The true incidence of allergic sensitization due to cephalosporins alone is difficult to assess, since in most patients treated with cephalosporins, the immune status for penicillin sensitivity before treatment is not objectively known and assessed. The general clinical impression is that in patients sensitized to benzyl-penicillin, overt allergic clinical reactions do not occur in more than 10%-20% of those subsequently treated with cephalosporins. The rate of adverse reactions may, however, be higher than suspected. In healthy volunteers given cephalothin and ce-phapirin intravenously, an unexpectedly high rate of reactions was experienced, and five patients developed skin hypersensitivity detected by skin test with PPL. 

A review of the use of cephalosporins in children with anaphylactic reactions to penicillins conclnded that there were no published case reports of anaphylaxis to these antibiotics in the assessed group and, in any case, anaphylaxis to cephalosporins was extremely rare in children. A prospective study of over 1,000 children with suspected immediate reactions to cephalosporins and/or penicillins showed that 58 % were skin or challenge test positive to a p-lactam with 94.4 % positive to penicillins and 35 % positive to cephalosporins. Approximately one-third of penicillin-allergic children cross-reacted with acephalosporin and those allergic to a cephalosporin showed an 84 % frequency of reactions to penicillins. Crossreactivity between cephalosporins was lower than CTOss-reactivity observed between cephalosporins... 

The question of tolerability of penicillins, monobactams, and carbapenems in patients with IgE hypersensitivity to cephalosporins was recently assessed in 98 subjects by serum IgE antibody assays, challenge tests, and skin testing with penicillin reagents, aztreonam, imipenem-cilastatin, and meropenem. Approximately 25 % of cephalosporin-allergic subjects were positive to penicillins, while 3.1,2, and 1 % showed positive results to aztreonam, imipenem, and meropenem, respectively. A reaction to a cephalosporin with a similar or identical side chain to penicillin was a sigifificant predictor of cross-reactivity. For skin testing, the following concentrations were used ampicillin and amoxicillin 1 and 20 mg/ml cephalosporins 2 mg/ml aztreonam 2 mg/ml imipenem-cilastatin 0.5 mg/ml and meropenem 1 mg/ml. 

The most common adverse reactions seen with administration of the cephalosporins are gastrointestinal disturbances, such as nausea, vomiting, and diarrhea Hypersensitivity (allergic) reactions may occur with administration of the cephalosporins and range from mild to life threatening. Mild hypersensitivity reactions include pruritus, urticaria, and skin rashes. More serious hypersensitivity reactions include S teveils-Johnson syndrome (fever, cough, muscular aches and... 

Some types of allergic reaction, for example immediate or delayed-type skin allergies, serum-sickness-like reactions and anaphylactic reactions, may occur in a proportion of patients given penicillin treatment. There is some, but not complete, cross-allergy with cephalosporins. 

Adverse reactions to cefuroxime have been generally mild and transient in nature. As with other cephalosporins there have been rare reports of erythema multiforme, Steven-Johnson syndrome, toxic epidermal necrolysis (exanthematic necrolysis) and hypersensitivity reactions including skin rashes, urticaria, pruritus, drug fever, serum sickness and very rarely anaphylaxis. 

Cephalosporins are sensitizing and may elicit a variety of hypersensitivity reactions that are identical to those of penicillins, including anaphylaxis, fever, skin rashes, nephritis, granulocytopenia, and hemolytic anemia. However, the chemical nucleus of cephalosporins is sufficiently different from that of penicillins so that some individuals with a history of penicillin allergy may tolerate cephalosporins. The frequency of cross-allergenicity between the two groups of drugs is uncertain but is probably around 5-10%. However, patients with a history of anaphylaxis to penicillins should not receive cephalosporins. 

Patients with a history of a reaction to penicillin are advised not to receive cephalosporins if they can be avoided. Patients who have negative penicillin skin tests or experienced only mild cutaneous reactions, such as macu-lopapular rashes, have a low risk of serious reactions to cephalosporins. 

Patients with delayed reactions to penicillin (skin rash) generally can receive cephalosporins. Patients with type I hypersensitivity reactions to penicillins (anaphylaxis) should not receive cephalosporins or carbapenems (alternatives include aztreonam, quinolones, sulfa drugs, or vancomycin based on type of coverage indicated). 

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. 

Immunologic Of 85 patients with a history of penicillin allergy and positive penicillin skin tests 5 (6%) had an adverse drug reaction to a cephalosporin compared with 5 (0.7%) of 726 patients with a history of penicillin allergy but negative penidllin skin tests [7. Presumed IgE-mediated adverse reactions to the cephalosporins occurred in 2 (2%) of the former compared with only 1 (0.1%) of the latter. 

Park MA, Koch CA, Klemawesch P, Joshi A, Li JT. Increased adverse drug reactions to cephalosporins in penicillin allergy patients with positive penicillin skin test. Int Arch Allergy Immunol 2010 153 (3) 268-73. 

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