A case of lupus erythematosus panniculitis misdiagnosed as vasculitis

We report a case of lupus erythematosus panniculitis misdiagnosed as vasculitis. A 7-year-old boy presented with a 2-year history of erythema and ulceration on the left lower abdomen and depressed skin on the left buttock. He had been diagnosed with vasculitis and skin infection in other hospitals for many times. Dermatological examination showed scattered dark erythema on the left lower abdomen, green bean to nail sized necrosis and ulcers with adhesive black crusts on some areas, and several porcelain-white mild atrophic scars. Non-atrophic band-like depression in normal color was observed on the left hip, ilium, left lower abdomen and the left groin. The skin could be pinched. Histopathological changes in the skin lesions included liquefaction degeneration of basal cells, pigment incontinence, infiltration of lymphocytes and plasma cells around dermal vessels and appendages, mucin deposition between collagen bundles, adipose atrophy, encapsulation of fatty lobules, and positive for Alcian blue staining. The final diagnosis was lupus erythematosus panniculitis. The patient was treated with oral hydroxychloroquine 0.1 g/qd and methylprednisolone 16 mg/qd, and topical mucopolysaccharide polysulfate cream, centella triterpenes cream and crisaborole ointment. Ulcers were healed without new lesion and erythema at one-year follow-up.