Vitamin B12 and folate deficiency are reversible causes of megaloblastic anemia. Strict vegetarians are at risk of megaloblastic anemia due to low cobalamin in their diet. Knuckle hyperpigmentation in patients with megaloblastic anemia is due to excess melanin synthesis in skin. Here we present a case of a young vegetarian male with megaloblastic anemia with knuckle hyperpigmentation managed successfully with intravenous followed by oral vitamin b12 and folate supplementation.

中文翻译：

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年轻男性指关节色素沉着过度：维生素 B12 缺乏症的一个不容忽视的临床症状

维生素 B12 和叶酸缺乏是巨幼细胞贫血的可逆原因。严格的素食者由于饮食中钴胺素含量低而面临巨幼细胞性贫血的风险。巨幼细胞性贫血患者指关节色素沉着过度是由于皮肤中黑色素合成过多所致。在此，我们介绍一例患有巨幼细胞性贫血的年轻素食男性，通过静脉注射和口服维生素 B12 和叶酸补充剂成功控制了指关节色素沉着。