Toxic epidermal necrolysis (TEN) is a critical life-threating condition developing as the total detachment of epidermidis and characterized by severe pathological reactions of all body systems. The current article describes two cases of TEN with similar clinical and laboratory signs. In one case the diagnosis of TEN was subsequently refused.The objective: analysis of methods of clinical and differential diagnostics of conditions accompanied with massive epidermidis detachment in ICU patients.Results. The immunomorphological evaluation of skin specimen obtained from the patient with a torpid form of TEN showed linear IgG fixation in the intercellular space of stratum basale, stratum spinosum and stratum granulosum and C3 fixation in the intercellular space of stratum basale.Conclusion. The complex of anamnesis data and pathomorphological evaluation of skin are crucial for the diagnosis and treatment of patients with atypical TEN.