Medical-Chinese loan-translation of Latin 'lupus erythematosus': 红斑 (red rash) + 狼 (wolf, from 'lupus') + 疮 (sore/ulcer). The 'wolf' refers to the old belief that the disfiguring facial rash looked like a wolf bite.
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Strictly medical vocabulary. The full clinical term 系统性红斑狼疮 (xìtǒngxìng ~) means 'systemic lupus erythematosus' (SLE).
