MDCalc

Penicillin Allergy Decision Rule (PEN-FAST)

Identifies low-risk penicillin allergies.

Five years or less since reaction

Anaphylaxis or angioedema

OR

Severe cutaneous adverse reaction

Treatment required for reaction

Result:

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Advice
  • Low-risk (score <3): Consider a direct oral or graded challenge.
  • Moderate- to high-risk (score ≥3): Refer to an allergist for a more detailed evaluation, which may include skin testing.
  • Document the PEN-FAST score and any subsequent allergy testing results in the medical record to support future clinical decisions.
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