• • Patients with any cephalosporin allergy have 25% cross-reactivity with penicillins 
  • Patients with a true allergy to penicillin have ~2% cross-reactivity with cephalosporins
  • Patients with cephalosporin allergy CAN be on a carbapenem
  • Patients with true allergy to penicillin, cross-reactivity with carbapenems is <10%, so do a test dose in the hospital if starting a carbapenem
  
  

  Posted 07/18/16 10:22:09 AM by Anna Krigel

• Type I (IgE-mediated) reaction
  
  
  • Sensitization stage - formation of drug specific IgE by drug-protein complex cross-linking with immunoglobulin surface receptors on B cells
  • Effector/Re-exposure stage - sensitized individual is re-exposed to the medication, drug cross-links with drug-specific IgE on the surface of mast cells and/or basophils, resulting in sudden and widespread release of vasoactive mediators
  
  

  Posted 07/18/16 10:47:29 AM by Anna Krigel

• Anaphylaxis
  • High output failure similar to sepsis
  • With allergic reaction, first figure out if it is anaphylaxis or not
  • about 1/4 will recur or present 5 hours after drug exposure as a late phase response to the allergic reaction
  • can present with abdominal cramping
  
  

  Posted 07/18/16 10:52:23 AM by Anna Krigel

• Anaphylaxis management
  1. EPINEPHRINE! - dose is 0.3-0.5mg of 1:1,000 concentration given intramuscularly, can be repeated every 5-15 minutes up to 3-4 doses
  2. IV fluids - to combat the massive capillary leak
  3. antihistamines - inhibit mediator release from mast cells/basophils, provides symptomatic relief
  4. corticosteroids - no immediate effects, used to prevent/mitigate potential delayed reaction
  
  

  Posted 07/18/16 11:01:29 AM by Anna Krigel

• For further reading...

  Anaphylaxis diagnostic criteria
  Cephalosporins in PCN-allergic patients
  
  

  Posted 07/18/16 11:03:33 AM by Anna Krigel

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