A Case of Erythema Elevatum Diutinum With Pancytopenia: Focus on Dapsone-Induced Hematologic Side Effects and Colchicine as a Safe Treatment Option

important role in the pathogenesis of EED.⁷ Deposition of immune complexes on the vessels can trigger the chain immunologic reaction to damage the vessels.⁸

The clinical differential diagnoses include Sweet’s syndrome, pyoderma gangrenosum, granuloma faciale, fixed drug reaction, erythema multiforme, lichen planus, porphyria cutanea tarda, fibrous histiocytoma or dermatofibroma, bacillary angiomatosis, Kaposi’s sarcoma, xanthoma, and necrobiotic xanthogranuloma.⁶

The histopathologic findings in EED vary depending upon the stage of the lesion. Early stage lesions show features of an acute leukocytoclastic vasculitis. This typically entails neutrophil permeation of vessels walls, fibrin thrombosis, and erythrocyte extravasation. A dermal mixed infiltrate of neutrophils, histiocytes, lymphocytes, and occasionally eosinophils accompanies the vasculitis. In its later stages, EED transitions to a fibrotic dermis. Still at this stage, occasional areas of neutrophilic vasculitis can be seen, while other vessels often show hyaline thickening. Extracellular lipid may be seen in the later stages, but cholesterol deposits are rare.⁵

The treatment of choice for EED is dapsone. To minimize the risk of life-threatening hemolytic anemia associated with dapsone, glucose-6-phosphate dehydrogenase deficiency should be screened before beginning therapy. A review of the literature reveals many other reported treatment options, including sulfapyridine, chloroquine, colchicine, tetracycline, niacinamide, and topical, intralesional, and systemic glucocorticoids. EED is a chronic condition with frequent recurrences after cessation of therapy.^5-9 Dapsone 100 mg daily remains the initial treatment of choice. The response may be partial and dose dependent. Dapsone may induce a dose-related hemolytic anemia, which is more likely with doses greater than 200 mg/day or in patients with glucose-6-phosphate dehydrogenase (G-6-PD) deficiency. Hematologic side effects include methemoglobinemia, aplastic anemia, leukopenia, agranulocytosis, eosinophilia, macrocytic anemia, and Heinz bodies. Leukopenia, megaloblastic pancytopenia, and hemolysis have been reported. At least one case of pure red cell aplasia has also been reported, in addition to a case of exanthema with desquamation of the trunk and extremities. Agranulocytosis usually occurs during the first few months of therapy and has been fatal. In one case report, filgrastim (G-CSF) was used to control the agranulocytosis.¹⁰ Linda Milkova et al informed asymptomatic dapsone-induced agranulocytosis in a patient with chronic spontaneous urticaria.¹¹

Aplastic anemia due to dapsone has been reported occasionally. The onset of aplastic anemia has ranged from 2 to 12 weeks following initiation of therapy and has been fatal. A 75-year-old male with granuloma annulare experienced pure