This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
[{'content': 'Dactylitis in children due to: \nSelect and explain. \nA. Sickle cell anemia, B. Thalassemia, C. Osteomyelitis, D. Hereditary spherocytosis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ref. The Short Textbook of Pediatrics. Pg 644\n\xa0\n\nDactylitis\xa0(also called hand-foot syndrome) is painful swelling of the hands or feet.\nThis is often the first symptom that may show up in small infants or\xa0toddlers\xa0with sickle cell disease.\xa0\nDactylitis\xa0is caused by sickled red blood cells blocking the small blood vessels in the hands and feet.\n\n\xa0\nOther causes\n\nTB\nSarcoidosis\nSyphilis\nSpondyloarthritis\nInfection - Commonly caused by skin infections, such as\xa0Streptococcus\xa0or\xa0Staphylococcus', 'role': 'assistant'}]