Frequent Cough and Blood-Tinged Sputum: Could It Be More Than Just a Cold?

How does modern medicine explain the lung parasite described in Donguibogam? The clearest clinical parallel is paragonimiasis. True to its name as a fluke that resides in the lungs, it occurs when freshwater crustaceans such as crabs or crayfish are eaten raw, allowing the parasite to enter the body and migrate to the lungs. While many people are familiar with Clonorchis sinensis or an intestinal fluke, a parasite living in the lungs may sound unfamiliar. Yet it is a condition with a long history that still occurs today in parts of Southeast Asia, Africa, and Korea. Once the fluke settles in the lungs, the body mounts a strong immune response to clear the foreign organism. This leads to a chronic cough that often worsens at night. Sputum frequently contains blood, sometimes taking on a rusty appearance. In more severe cases, symptoms such as chest pain, dyspnea, fever, and chills appear, making it easy to mistake the condition for pneumonia or tuberculosis. On an X-ray or computed tomography scan, the lesion can appear as a shadow resembling a tumor, occasionally leading to a misdiagnosis of lung cancer. For this reason, when an unexplained cough and hemosputum persist, reviewing dietary history—such as eating raw freshwater foods—or past travel history is an important diagnostic step. Like many parasitic conditions, paragonimiasis often presents with an elevated eosinophil count on a blood test. A definitive diagnosis is made by identifying helminth eggs in sputum or stool, or by detecting specific antibodies through a blood test. Once identified, it can be treated relatively simply with praziquantel. However, without timely diagnosis and treatment, it can progress to complications such as lung fibrosis or an abscess, meaning persistent symptoms should never be ignored. If these symptoms continue, rather than relying solely on cold medications or an antibiotic, ask your physician about the possibility of a parasitic infection. Those who have consumed raw freshwater crabs, crayfish, or raw freshwater fish should be particularly mindful. Listening carefully to the signals the body provides is essential for catching such conditions early.