Abstract: A 49-year-old male presented with erythema, papules, blisters and erosion all over the body with itching and pain for more than 10 days. The patient was treated with oral almonertinib mesylate for lung adenocarcinoma with pleural metastasis. Erythema and papules appeared on the face and trunk after half a month later, and symptomatic treatment did not improve, with large area of skin exfoliation, erosion, and exudation. The diagnosis of toxic epidermal necrolysis was made. The drug was stopped immediately and systemic corticosteroids and gamma globulin were used. The lesions gradually subsided.

Key words: almonertinib mesylate')">">almonertinib mesylate, bullotic toxic epidermal necrolysis, adverse drug reaction