Β-lactam allergy: Difference between revisions

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Β-lactam allergy
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{{DISPLAYTITLE:β-lactam allergy}}
==Cross-reactivity==

==Cross-Reactivity==

* Cross-reactivity between [[penicillins]] and [[cephalosporins]] is mediated by homology of the R1 side chains, referring to the C6 side chain in [[penicillins]] or the C7 side chain in [[cephalosporins]]
* Cross-reactivity within [[cephalosporins]] is mediated both by homology of the R1 side chains and also R2 side chains, referring to the C3 side chain


{| class="wikitable"
{| class="wikitable"
! rowspan="2" |Antibiotic
! rowspan="2" |Antibiotic
! colspan="3" align="center" |C7
! colspan="3" align="center" |R1
! colspan="7" align="center" |C3
! colspan="7" align="center" |R2
|-
|-
!G1
!G1
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|}
|}


===C-7 Side Chains===
===R1 Side Chains (C6 and C7)===


*'''Group 1:''' [[penicillin]], [[cephalothin]], [[cefoxitin]]
*'''Group 1:''' [[penicillin]], [[cephalothin]], [[cefoxitin]]
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*'''Group 3:''' [[cefipime]], [[cefotaxime]], [[ceftriaxone]]
*'''Group 3:''' [[cefipime]], [[cefotaxime]], [[ceftriaxone]]


===C-3 Side Chains===
===R2 Side Chains (C3)===


*'''Group 1:''' [[cefadroxil]], [[cephalexin]]
*'''Group 1:''' [[cefadroxil]], [[cephalexin]]
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[[Category:Antibiotics]]
[[Category:Antibiotics]]
[[Category:Immunology]]

Revision as of 14:12, 16 September 2020


Cross-Reactivity

  • Cross-reactivity between penicillins and cephalosporins is mediated by homology of the R1 side chains, referring to the C6 side chain in penicillins or the C7 side chain in cephalosporins
  • Cross-reactivity within cephalosporins is mediated both by homology of the R1 side chains and also R2 side chains, referring to the C3 side chain
Antibiotic R1 R2
G1 G2 G3 G1 G2 G3 G4 G5 G6 G7
Penicillin X
Ampicillin X
Amoxicillin X
Cefazolin
Cephalexin X X
Cefadroxil X X
Cephalothin X X
Cefotetan X
Cefoxitin X X
Cefuroxime X
Cefaclor X
Cefotaxime X X
Ceftriaxone X
Ceftazidime X
Cefixime X
Cefdinir
Cefipime X
Ceftaroline

R1 Side Chains (C6 and C7)

R2 Side Chains (C3)

Hypersensitivity Reactions

  • Type I (IgE-mediated)
    • Anaphylaxis
    • Itchy rash
    • Penicillins should be avoided
  • Type II (IgG-mediated)
    • Non-itchy rash
    • Rash will improve if treatment continues, no need to avoid penicillins
  • Type IV (cell-mediated)
    • Toxic epidermal necrolysis
    • Stevens-Johnson syndrome
    • Penicillins should be avoided

Further Reading

  • Zagursky RJ and Pichichero ME. Cross-reactivity in β-Lactam Allergy. J Allergy Clin Immunol Pract. 2018;6(1):72-81.e1. doi: 10.1016/j.jaip.2017.08.027