The role and histopathology of oral drug challenge in the evaluation of fixed drug eruptions

Abstract

This case series describes the role of oral drug challenge in the diagnosis of fixed drug eruption in the setting of polypharmacy. Practical testing guidelines are provided. The literature describing the histopathology of acute fixed drug reaction is also reviewed and compared with the findings in this series.

A Review of Fixed Drug Eruption with a Special Focus on Generalized Bullous Fixed Drug Eruption

“…A recent case series proposed new guidelines for safely performing oral challenge tests, even in patients with a history of generalized FDE [35]. For patients who presented with less than three lesions of FDE, the authors recommended starting with the standard average daily dose and, if no reaction is seen, increasing to twice the daily dose [35]. If twice the daily dose does not result in a reaction, the drug is excluded as the cause of FDE.…”

“…If twice the daily dose does not result in a reaction, the drug is excluded as the cause of FDE. For patients who presented with more than three FDE lesions or had oral involvement, the authors recommended a graded oral challenge [35]. The graded challenge starts with 20% of the daily dose and increases by ten percent every 30 min until the patient develops lesions of FDE or a cumulative dose of twice the average daily dose is reached [35].…”

“…For patients who presented with more than three FDE lesions or had oral involvement, the authors recommended a graded oral challenge [35]. The graded challenge starts with 20% of the daily dose and increases by ten percent every 30 min until the patient develops lesions of FDE or a cumulative dose of twice the average daily dose is reached [35]. This case series was limited to two patients, however, and one of them developed new FDE lesions with the graded oral challenge test in addition to recurrence of FDE at prior sites of involvement [35].…”

“…The graded challenge starts with 20% of the daily dose and increases by ten percent every 30 min until the patient develops lesions of FDE or a cumulative dose of twice the average daily dose is reached [35]. This case series was limited to two patients, however, and one of them developed new FDE lesions with the graded oral challenge test in addition to recurrence of FDE at prior sites of involvement [35]. Further studies will need to be done to determine the safety of these proposed guidelines.…”