Β-lactam allergy: Difference between revisions

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Β-lactam allergy
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===R1 Side Chains (C6 and C7)===
====R1 Side Chains (C6 and C7)====


*'''Group 1:''' [[penicillin]], [[cephalothin]], [[cefoxitin]]; similar to [[ticarcillin]]
*'''Group 1:''' [[penicillin]], [[cephalothin]], [[cefoxitin]]; similar to [[ticarcillin]]
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*[[Ceftazidime]] and [[aztreonam]]; similar to group 3
*[[Ceftazidime]] and [[aztreonam]]; similar to group 3


===R2 Side Chains (C3)===
====R2 Side Chains (C3)====


*'''Group 1:''' [[cefadroxil]], [[cephalexin]]
*'''Group 1:''' [[cefadroxil]], [[cephalexin]]
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*'''Group 6:''' [[cefixime]]
*'''Group 6:''' [[cefixime]]
*'''Group 7:''' [[ceftazidime]]
*'''Group 7:''' [[ceftazidime]]

== Management ==

=== Penicillin Allergy ===

* Consider skin testing

{| class="wikitable"
!Class
!Cross-reactivity
!Notes
|-
|Cephalosporin, 1st generation
|2-8%
|Based on poor studies. Avoid cephalexin and cefaclor in ampicillin allergy.
|-
|Cephalosporin, 2nd generation
|2%
|Avoid cefoxitin in penicillin allergy. Avoid cefadroxil and cefprozil in amoxicillin allergy).
|-
|Cephalosporin, 3rd generation
|<1%
|Generally considered safe.
|-
|Cephalosporin, higher generation
|N/A
|No data available, but generally considered safe.
|-
|Carbapenem
|1%
|Generally considered safe.
|-
|Monobactam
|<1%
|Avoid aztreonam in ceftazidime allergy.
|}

* For those with penicillin allergy
** 1st gen cephalosporins: cross-reactavoid cephalexin and cefaclor if ampicillin allergic
** 2nd gen cephalosporins:


==Further Reading==
==Further Reading==

Revision as of 17:56, 11 February 2021


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

Cross-Reactivity

  • The following applies to immediate, IgE-mediated hypersensitivity reactions
  • Cross-reactivity within penicillins is mediated by homology of the R1 side chain (referring to the C6 side chain) and by the β-lactam ring itself
  • 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)
  • There is very low (~2%) cross-reactivity between penicillin allergy and carbapenems1
Antibiotic R1 R2
G1 G2 G3 G1 G2 G3 G4 G5 G6 G7
Penicillins
Penicillin X
Ampicillin X
Amoxicillin X
First-Generation Cephalosporins
Cefazolin
Cephalexin X X
Cefadroxil X X
Cephalothin X X
Second-Generation Cephalosporins
Cefotetan X
Cefoxitin X X
Cefuroxime X
Cefaclor X
Third-Generation Cephalosporins
Cefotaxime X X
Ceftriaxone X
Ceftazidime X
Cefixime X
Cefdinir
Fourth-Generation Cephalosporins and Higher
Cefipime X
Ceftaroline

R1 Side Chains (C6 and C7)

R2 Side Chains (C3)

Management

Penicillin Allergy

  • Consider skin testing
Class Cross-reactivity Notes
Cephalosporin, 1st generation 2-8% Based on poor studies. Avoid cephalexin and cefaclor in ampicillin allergy.
Cephalosporin, 2nd generation 2% Avoid cefoxitin in penicillin allergy. Avoid cefadroxil and cefprozil in amoxicillin allergy).
Cephalosporin, 3rd generation <1% Generally considered safe.
Cephalosporin, higher generation N/A No data available, but generally considered safe.
Carbapenem 1% Generally considered safe.
Monobactam <1% Avoid aztreonam in ceftazidime allergy.
  • For those with penicillin allergy
    • 1st gen cephalosporins: cross-reactavoid cephalexin and cefaclor if ampicillin allergic
    • 2nd gen cephalosporins:

Further Reading

  • 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
  • Cross-Reactivity to Cephalosporins and Carbapenems in Penicillin-Allergic Patients: Two Systematic Reviews and Meta-Analyses. J Allergy Clin Immunol Pract. 2019;7(8):2722-2738.e5. doi: 10.1016/j.jaip.2019.05.038

References

  1. ^  Brittany Kula, Gordana Djordjevic, Joan L. Robinson. A Systematic Review: Can One Prescribe Carbapenems to Patients With IgE-Mediated Allergy to Penicillins or Cephalosporins?. Clinical Infectious Diseases. 2014;59(8):1113-1122. doi:10.1093/cid/ciu587.