INTRODUCTION
Adverse drug events (ADEs), or injury resulting from a medical intervention related to a drug, can happen in the outpatient setting. Specifically, in the outpatient setting, ADEs accounts for over 2.5 million physician office visits and approximately 125,000 hospital admissions each year.1 A specific form of ADE is drug re-exposure. Drug re-exposure can result from both patient and prescriber factors. Patient factors include polypharmacy, medical illiteracy,2 living alone, and older age. Retention of discontinued medications and self-prescribing practices also play a role.3 As it pertains to prescribers, relying on the electronic medical records (EMR) or pharmacies to accurately detect and catalog allergies at the time of dispensing is not realistic as 43% of patients use multiple pharmacies.4
Severe cutaneous adverse drug reactions, such as Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), can be a rare, but life-threatening result of medication re-exposure. SJS/TEN span the continuum of epidermolytic cutaneous reactions, and mortality ranges from less than 10 percent in SJS to over 30 percent with TEN. Patients who recover from a severe adverse reaction to a medication may be at risk for SJS/TEN upon re-exposure as they maintain a long-term cytotoxic memory response to the inciting drug.5 In SJS/TEN re-exposure has an incidence of up to 18%,6,7 and leads to severe acute SJS/TEN, especially in instances of multiple recurrences.8
Severe cutaneous adverse drug reactions, such as Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), can be a rare, but life-threatening result of medication re-exposure. SJS/TEN span the continuum of epidermolytic cutaneous reactions, and mortality ranges from less than 10 percent in SJS to over 30 percent with TEN. Patients who recover from a severe adverse reaction to a medication may be at risk for SJS/TEN upon re-exposure as they maintain a long-term cytotoxic memory response to the inciting drug.5 In SJS/TEN re-exposure has an incidence of up to 18%,6,7 and leads to severe acute SJS/TEN, especially in instances of multiple recurrences.8
CASES
In this series, we report a single-center experience of TEN as a result of drug re-exposure. Five patients were evaluated by an inpatient dermatology consult service and found to have drug re-exposure-induced TEN (Table 1). Diagnosis was made based on clinical findings9 and supporting cutaneous histopathology, when available. Initial drug exposure resulted in sensitization that presented with a variety of severe reactions including SJS, but also pancytopenia, facial swelling, and a painful rash with fever.
Upon re-exposure, a single dose of the offending drug class was sufficient to induce TEN. Distinct temporal relationships with re-exposure to the offending agents was noted to be within 14 days for sulfadiazine, within 72 hours for TMP-SMX, and within a few hours for aromatic anti-epileptic class drugs. Average SCORTEN9 score on arrival was 2.6. Average body surface area (BSA) involved was 73%. Failure to recognize the offending agent (Patient 1), failure to reconcile allergies (Patients 2 and 4), and self-medicating (Patients 3 and 5), contributed to re-exposure (Table 1).
All five patients were admitted to the burn intensive care unit and received supportive care; and additionally, received systemic corticosteroids, intravenous immunoglobulin or both. Two patients succumbed to TEN within 10 days of hospitalization and one was discharged to hospice.
Upon re-exposure, a single dose of the offending drug class was sufficient to induce TEN. Distinct temporal relationships with re-exposure to the offending agents was noted to be within 14 days for sulfadiazine, within 72 hours for TMP-SMX, and within a few hours for aromatic anti-epileptic class drugs. Average SCORTEN9 score on arrival was 2.6. Average body surface area (BSA) involved was 73%. Failure to recognize the offending agent (Patient 1), failure to reconcile allergies (Patients 2 and 4), and self-medicating (Patients 3 and 5), contributed to re-exposure (Table 1).
All five patients were admitted to the burn intensive care unit and received supportive care; and additionally, received systemic corticosteroids, intravenous immunoglobulin or both. Two patients succumbed to TEN within 10 days of hospitalization and one was discharged to hospice.
