A 84-year-old female noticed erythema over her whole body for several months and was referred to our department for evaluation of her skin eruption. A physical examination revealed millet-sized erythematous papules and macules all over her body, a high body temperature, and a decreased level of consciousness. A laboratory examination showed an elevated white blood cell count (8200/μl), atypical lymphocytes (3%) and sIL-2R (4030U / ml). Computed Tomography showed systemic lymphadenopathy. A lymph node biopsy taken from the left inguinal lymph node revealed destruction of the lymph nodes, enlargement of the high endothelial venules, and atypical lymphocyte infiltration. Based on the clinical findings and laboratory examination, we diagnosed angioimmunoblastic Tcell lymphoma (AITL). AITL is a relatively rare peripheral T-cell lymphoma with severe systemic symptoms such as fever and lymph node swelling. While approximately half of all cases experience skin symptoms, which are one of the initial symptoms, it is difficult to determine the diagnosis due to the various clinical features or many non-specific rashes. We should keep in mind a differential diagnosis of lymphoma in cases of the presence of persistent eruption, systemic symptoms, and the existence of atypical lymphocytes in peripheral blood.