Β-lactam allergy: Difference between revisions

Revision as of 10:51, 16 September 2020

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 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
Antibiotic	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)

Group 1: penicillin, cephalothin, cefoxitin; similar to ticarcillin
Group 2: amoxicillin, ampicillin, cefaclor, cephalexin, cefadroxil; similar to penicillin piperacillin
Group 3: cefipime, cefotaxime, ceftriaxone; similar to ceftazidime and aztreonam
Ceftazidime and aztreonam; similar to group 3

R2 Side Chains (C3)

Group 1: cefadroxil, cephalexin
Group 2: cefotetan
Group 3: cefotaxime, cephalothin
Group 4
Group 5: cefuroxime, cefoxitin
Group 6: cefixime
Group 7: ceftazidime

References

^ 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.

@@ Line 1: / Line 1: @@
 {{DISPLAYTITLE:β-lactam allergy}}
+==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 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 [[carbapenems]][[CiteRef::kula2014a]]
 {| class="wikitable"
@@ Line 265: / Line 281: @@
 *'''Group 6:''' [[cefixime]]
 *'''Group 7:''' [[ceftazidime]]
-==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==