Singer and Wallace listed criteria for diagnosing the Allopurinol Hypersensitivity Syndrome (AHS, Allopurinol-related DRESS), a potentially life-threatening condition. The authors are from the State University of New York Health Sciences Center in Brooklyn.


Criteria for the diagnosis of AHS:

(1) one of the following:

(1a) 2 or more major criteria

(1b) 1 major and 1 or more minor criteria

(2) documented exposure to allopurinol

(3) exclusion of an alternative explanation (exposure to a different drug associated with the drug rash with eosinophilia and systemic symptoms (DRESS)


Major criteria:

(1) deterioration in renal function

(2) acute hepatocellular injury

(3) any of the following: toxic epidermal necrolysis, erythema multiforme, diffuse maculopapular rash, exfolliative dermatitis


Minor criteria:

(1) fever

(2) leukocytosis

(3) eosinophilia


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