Cold agglutinin disease (CAD) is extremely rare in children. We report an 8-year-old boy who presented with gangrene of right foot with hypertension and absent lower limb pulses. Blood peripheral smear evidence of autoagglutination and falsely elevated red blood cell indices were suggestive of CAD and on subsequent investigations he was found to have high titres of cold agglutinin antibodies. He also had evidence of pneumonia on chest X-ray and serology for mycoplasma was positive. Computed tomography angiography showed multifocal thrombotic occlusion in bilateral popliteal arteries. He was effectively managed using antimicrobials, warm clothing, aspirin, anticoagulation and corticosteroids. He remains clinically well on follow-up and had no recurrence. CAD presenting with peripheral gangrene is extremely unusual. A careful look at peripheral blood smear gives an initial diagnostic clue. CAD triggered by infection is often self-limiting and requires supportive care.

冷凝集素病 (CAD) 在儿童中极为罕见。我们报告了一名 8 岁男孩，他出现右脚坏疽伴高血压和下肢脉搏消失。血液外周涂片显示自身凝集和红细胞指数虚假升高提示 CAD，随后的调查发现他有高滴度的冷凝集素抗体。他的胸部 X 光片也有肺炎证据，支原体血清学呈阳性。计算机断层扫描血管造影显示双侧腘动脉多灶性血栓性闭塞。使用抗菌剂、保暖衣物、阿司匹林、抗凝剂和皮质类固醇有效地管理了他。随访时临床表现良好，未复发。伴有周围坏疽的 CAD 极为罕见。仔细观察外周血涂片可以提供初步诊断线索。由感染引发的 CAD 通常是自限性的，需要支持性护理。