What are the distinct features of MTX-induced epidermal necrosis?
Methotrexate-induced epidermal necrosis (MEN) presents clinicopathologic features that are different from Stevens‒Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), according to a study.
“Recognition of the early signs and prognostic factors is important, because the rapid institution of leucovorin may be helpful,” researchers said.
A total of 24 patients with MEN and 150 controls were included in this study, which examined the clinicopathology, risk factors and prognostic factors of MEN. The authors analysed the demographics, pathology and plasma concentrations of methotrexate (MTX).
Extensive skin necrosis (mean 33.2 percent total body surface), but no target lesion, was present in patients with MEN. The histopathology exhibited keratinocyte dystrophy. Furthermore, painful skin erosions, oral ulcers and leukopaenia/thrombocytopaenia were early indicators of MEN.
There was 16.7-percent mortality despite administration of leucovorin to majority of the patients (79.2 percent).
Older age (>60 years), chronic kidney disease and high initial dosage of MTX without folic acid supplementation predicted MEN. MTX clearance was delayed by renal insufficiency.
Severe renal disease and leukopaenia were predictors of poor prognosis in MEN, but none of the Score of Toxic Epidermal Necrosis criteria correlated with mortality of MEN.
The major limitation of this study was its small sample size.
According to researchers, physicians should avoid prescribing MTX to high-risk patients and titrate the dosage slowly upward with folic acid supplementation to lower the risk of MEN, which is a rare but life-threatening cutaneous reaction that mimics SJS/TEN.