II. History: Reaction

  1. How old were you when you had the reaction?
  2. Did Type 1 Hypersensitivity Reaction symptoms occur?
    1. Anaphylaxis
    2. Hypotension
    3. Laryngeal edema (Wheezing or Stridor)
    4. Angioedema
    5. Urticaria
  3. How soon after the medication did the reaction start?
    1. Within one hour suggests Type 1 Hypersensitivity
  4. Was the Penicillin given orally or parenterally?
  5. Did the reaction resolve after stopping the medication?
  6. Have you taken related medications and did you react?
    1. Amoxicillin or Augmentin?
    2. Cephalosporin

III. Management

  1. Cephalosporins have cross reactivity with Penicillins
    1. Cross reactivity was originally over-estimated as high as 10% in the 1960s
      1. Attributed to cross contamination
      2. Co-production of Cephalosporins and Penicillins in the same factory
    2. Cephalosporin reaction when Penicillin Allergy
      1. Penicillin Allergy and allergy to first and Second Generation Cephalosporins: 1%
      2. Penicillin Allergy and allergy to Third Generation Cephalosporins: Negligible
      3. Aminopenicillins (Amoxicillin and Ampicillin) allergy
        1. Cross-reactivity to first and Second Generation Cephalosporins: High
        2. R1-side chain of Aminopenicillins are similar to first and Second Generation Cephalosporins
        3. Reaction rate is as high as 27% for Cefadroxil
      4. Campagna (2012) J Emerg Med 42(5): 612-20 [PubMed]
    3. Penicillin Allergy when Cephalosporin allergic: >25%
    4. Cephalosporin cross reactivity risk factors
      1. Type I Hypersensitivity to Penicillin
      2. Positive Penicillin skin test (5% risk)
      3. First or second generation Cephalosporin
      4. Atopic Dermatitis
  2. Reaction not consistent with Type I Hypersensitivity
    1. Consider Penicillin Skin Testing for allergy
    2. Continue to avoid Penicillins unless otherwise directed by allergy Consultation
    3. Cephalosporins may be used
      1. Some recommend penicillin Skin Testing before use
      2. Kelkar (2001) N Engl J Med 345:804-9 [PubMed]
  3. Type I Hypersensitivity Reaction
    1. Obtain Penicillin Skin Testing for allergy
    2. Penicillin skin test negative (80-95% of cases)
      1. Cephalosporins may be used (1.3% risk of reaction)
      2. Continue to avoid Penicillins unless otherwise directed by allergist
    3. Penicillin skin test positive
      1. Avoid Penicillins and Cephalosporins
      2. Risk of Cephalosporin reaction: 4.4%
      3. Consider Cephalosporin desensitization

IV. Complications

  1. Documented Penicillin Allergy is associated with adverse events due to alternative antibiotic use
    1. Confirm allergy and document actual Penicillin reaction
    2. Results in overuse of broad spectrum agents
    3. Associated with longer hospital stay and increased C. Diff and MRSA Infections
    4. Macy (2014) J Allergy Clin Immunol 133(3): 790-6 +PMID:24188976 [PubMed]

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Ontology: Allergy to penicillin (C0030824)

Concepts Disease or Syndrome (T047)
SnomedCT 91936005
Dutch penicillineallergie
French Allergie à la pénicilline
German Penicillinallergie
Italian Allergia alla penicillina
Portuguese Alergia a penicilina
Spanish Alergia a la penicilina, alergia a la penicilina (trastorno), alergia a la penicilina
Japanese ペニシリンアレルギー, ペニシリンアレルギー
Czech Alergie na penicilin
English allergy penicillins, pcn allergy, allergy to penicillin, allergies penicillin, allergy penicillin, penicillin allergy, Penicillin allergy, Allergy to penicillin, Allergy to penicillin (disorder), Penicillin Allergy
Hungarian Penicillin-allergia

Ontology: Adverse reaction to penicillins (C0413443)

Concepts Injury or Poisoning (T037)
ICD9 E930.0
ICD10 Y40.0 , T36.0X5
SnomedCT 222951008, 158009006, 218258003, 218277001, 292954005
English Penicillins, Penicillins causing adverse effects in therapeutic use, AR - penicillin NOS, AR - penicillins, Adverse effects in the therapeutic use of penicillins, Adverse reaction to penicillin NOS, Adverse reaction to penicillins, Penicillin caus adv eff, [X]Penicillin caus adv eff, [X]Penicillins causing adverse effects in therapeutic use, penicillin reaction, Adv eff penicillins, Adverse effect;penicillin, Adverse effect of penicillins, adverse reaction to penicillin, adverse effect of drug therapy antibiotics penicillin, adverse effect of drug therapy antibiotics penicillin (diagnosis), [X]Penicillins causing adverse effects in therapeutic use (disorder), Adverse reaction to penicillin NOS (disorder), Adverse reaction to penicillins (finding), Adverse reaction to penicillins (disorder), Penicillin adverse reaction, Penicillin adverse reaction (disorder), Adverse reaction to penicillin NOS (finding), [X]Penicillins causing adverse effects in therapeutic use (finding)
Spanish [X]penicilinas que producen efectos adversos en el uso terapéutico (hallazgo), reacción adversa a penicilina, SAI, [X]penicilinas que producen efectos adversos en el uso terapéutico, [X]penicilinas que producen efectos adversos en el uso terapéutico (trastorno), reacción adversa a penicilinas (hallazgo), reacción adversa a penicilinas, reacción adversa a penicilina, SAI (trastorno), reacción adversa a la penicilina (trastorno), reacción adversa a la penicilina, reacción adversa a penicilina, SAI (hallazgo)
German Unerwuenschte Nebenwirkungen bei therapeutischer Anwendung: Penizilline
Korean 페니실린
Dutch Penicillinen