c2 Penicilloyl V

Allergens within Drugs

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Less than 10% of all adverse reactions to drugs have an immunological background, and only a part of those are IgE-mediated (1).

Allergen Exposure

Drug therapy.
Food consumption from animals treated with penicillin.
Exposure in fetuses or babies from pregnant or nursing mothers treated with penicillin.

Potential Cross-Reactivity

Extensive cross-reactivity exists between different penicillins (2). However, side-chain specific immune responses have been reported in a number of cases, which supports the utility of diagnostic tests with different penicillin allergens (3). Cross-reactivity also exists between penicillins and cephalosporins, but its extent is largely unknown (4).

Clinical Experience

We can use the Gell and Coombs classification to subdivide allergic reactions into immunopathological mechanisms.
Type I hypersensitivity reactions are IgE-mediated and can be immediate (<1 hour after penicillin administration) or accelerated (1-72 hours after administration). The clinical picture consists of anaphylaxis, angioedema and some forms of urticaria. Late reactions (>72 hours) are often unrelated to IgE antibodies.
 
Review
B-lactam antibiotics, including the penicillins and the cephalosporins, are the most common causes of drug-induced hypersensitivity. Allergen exposure can be via drug therapy, food consumption from animals treated with penicillin, exposure in fetuses or babies from pregnant or nursing mothers treated with penicillin, and occupational exposure. Theoretically, skin tests can also lead to occupational exposure.
 
Prevalence
The proportion of the U.S. population reporting a history of penicillin allergy has been estimated to vary from 0.7 to 10% of treated patients. Immediate systemic reactions, or anaphylaxis, occur in about 0.01% of treated patients (1).
 
Allergen structure
The major allergenic determinant in penicillin allergy is the penicilloyl group bound by an amide linkage to e-amino-groups of lysine residues in proteins. 
 

References:

    1. Idsoe O, Guthe T, Wilcox RR, de Weck AL. Nature and extent of penicillin side-reactions, with particular reference to fatalaties from anaphylactic shock. Bull WHO 1968;38:159-188.
    2. Adkinson Jr NF. Beta-lactam crossreactivity. Clin Exp Allergy 1998;28(Suppl 4):37-40.
    3. Vega JM, Blanca M, Garcia JJ, Carmona MJ, Miranda A, Pérez-Estrada M et al. Immediate allergic reactions to amoxicillin. Allergy 1994;49;317-22.
    4. Kishiyama, JL; Adelman, DC. The cross-reactivity and immunology of b-lactam antibiotics. Drug Safety 1994;10;318-27.

2000



Further Reading