A case of histopathologically typical toxic epidermal necrolysis despite no visible blisters or erosive lesions.

Toxic epidermal necrolysis (TEN) is a rare life-threatening disease characterized by blister formation and erosion over the entire body surface resulting from extensive keratinocyte death. We reported a case of TEN that developed in a 68-year-old man with hepatitis C virus liver cirrhosis three weeks after treatment with allopurinol. Exanthema developed as multiple target-like lesions, and erythroderma within five days without forming visible erosive lesions or obvious mucous membrane involvement. Reactivation of human herpes virus-6 or other herpes virus was not detected by polymerase chain reaction or serologic studies, and drug-induced hypersensitivity syndrome was ruled out. The finding of panepidermal necrosis on histopathological examination led to a diagnosis of TEN. Exanthema, fever and renal dysfunction responded to oral prednisolone, but the patient died of liver failure. Cases of TEN with histopathologically proven panepidermal necrosis without apparent blisters or erosions have rarely been reported because they do not fulfill the previously proposed diagnostic criteria for TEN. This finding, the discrepancy between the clinical and the histopathological manifestations, should not be overlooked in a case suspicious of TEN, and the importance of the histopathological examination should be emphasized in the differential diagnosis of TEN.