Case presentation
A 31-year-old woman presented with a 1-year history of purplish-red papules, nodules, and blisters symmetrically distributed on her scalp, trunk, and limbs (Fig. 1). The patient had a previous history of pulmonary tuberculosis. Laboratory test results of the patient show elevated serum levels of IgG (356.2 mg/dL; normal range, 60–160mg/dL) and IgA (37.6 mg/dL; normal range, 7–36 mg/dL). Reduced level of C3 (75 mg/dL; normal range, 79–152 mg/dL) and C4 (12 mg/dL; normal range, 16–38 mg/dL) were observed. A monoclonal band was observed as IgA-λ paraprotein on serum electrophoresis. The serum complement profile showed reduction of C3 (64.8 mg/dL; normal range, 79–152 mg/dL) and C4 (11.9 mg/dL; normal range, 16–38 mg/dL). Examinations for hepatitis B and HIV were negative. Full blood count, renal and liver function tests, and autoimmune antibodies such as antinuclear antibodies were all within the normal range. A biopsy from the left foot specimen presented a significant increase of neutrophils, fragmented nuclei, and fibrinoid necrosis of vascular tissue in the middle and deep layers of the dermis (Fig. 2).
According to the clinical manifestation and auxiliary examination results, the diagnosis of erythema elevatum diutinum was considered. Initial therapy included methylprednisolone and dapsone, beginning at 40mg/d and 100mg/d, respectively. Colchicine 1g/d and dapsone 200mg/d were subsequently added to her treatment regimen because this patient had a poor response to dapsone and corticosteroid and her condition continued to deteriorate. Subsequently, after continuous IVIg (intravenous immunoglobulin) 22.5g/d for 5 days, the patient’s condition was quickly stabilized. After a one-month follow-up, most of the plaques subsided and the papules flattened.