A Case of Erythema Induratum of Bazin with Migratory Erythema at Unilateral Lower Limb

Abstract

A 77-year-old woman presented with painful erythematous nodules on the anterior aspect of the right lower limb. They regressed by topical corticosteroids without ulceration ; however, shortly afterwards, new similar lesions appeared on the medial aspect nearby the previous lesions. They progressed to the posterior aspect and became refractory. A skin biopsy revealed lobular granulomatous panniculitis without caseous necrosis. She had a past medical history of pulmonary tuberculosis 27 years ago. She underwent an interferon-gamma release assay test and a tuberculin reaction test, both of which were positive. Although active tuberculous lesions were not found in other organs, she was treated with tuberculostatic drugs in consultation with pulmonologists. The lesions showed a good clinical response and regressed in about 3 months. Therefore, she was diagnosed with erythema induratum of Bazin (EI). Recently, reports of atypical cases of EI are increasing in Japan. It is suspected that this trend may be related to an increase in the aging population of patients and changes in their immune status by immunosuppressant and underlying diseases. In the present study, the atypical clinical presentation was associated with the advanced age and the medical history of the patient, as she had developed malignant tumors twice in the past. Furthermore, the diagnosis and recovery were delayed because the lesions were unilateral and seemed to be in a remission. Therefore, it is crucial to be familiar with characteristics of EI,including atypical cases, for early intervention. Skin Research, 21 : 6-9, 2022