Angioimmunoblastic T-cell lymphoma is an aggressive subtype of peripheral T-cell non-Hodgkin lymphoma with diverse cutaneous manifestations. Because there are no specific diagnostic criteria for cutaneous clinical and histopathological findings, reaching a correct diagnosis solely based on dermatological examination is immensely challenging. A 59-year-old female presented with pruritic widespread erythematous confluent papules and plaques with edematous malar rash on both cheeks, mimicking systemic contact dermatitis, drug eruptions, and lupus erythematosus. However, there were no significant foods, allergens, and changes of drugs related to the causes. Skin biopsy revealed dermal perivascular infiltrates of lymphocytes and neutrophils with no specifically confirmed disease entity. Steroid pulse therapy was started, which seemingly showed a clinical improvement; however, generalized edematous skin eruption recurred with fever and swelling of the neck. Lymph node biopsy finally revealed angioimmunoblastic T-cell lymphoma. The patient was eventually transferred to the department of medical oncology and hematology for chemotherapy, which was ineffective to stop the fatal outcome. Herein, we report a patient, who was initially diagnosed as systemic contact dermatitis, later confirmed to be angioimmunoblastic T-cell lymphoma upon lymph node biopsy.