The fingernails have a mica-like appearance. There are many types of parasites, and the parasitic process in the human body is complex, and their various developmental stages are not always in the intestine, so the lesions caused are not limited to the intestine. The following diseases are the causes of nails similar to mica: 1, pulmonary ascariasis Mainly respiratory lesions caused by the migration of roundworms, ectopic parasitism of adult worms and deposition of eggs in the lungs, accounting for the second place of ectopic ascariasis (the first place is biliary ascariasis). 2, orbital parasitic cysts Parasitic cysts can occur in the orbit. The most common parasite in inflammatory lesions of cysts is T. echinococcus, the larvae of which are called fine-grained echinococcosis, which produces lesions called echinococcosis (echinocysts) cysts that can metastasize and spread to various organs throughout the body, including the orbit, via blood and lymphatic flow. 3.Biliary ascariasis and hepatic ascariasis Biliary ascariasis and hepatic ascariasis are two closely related and distinct diseases, both of which originate from intestinal roundworms. 1932, British doctor Mure performed the first case of choledochotomy to remove roundworms in China, and in 1942, the second case of choledochotomy to remove roundworms was performed by Huaxi Medical University, thus opening a new page of biliary surgery in the East. Since the discovery of biliary ascaris, this disease has been rampant in China for at least half a century and has become an important cause of primary hepatic bile duct stones. Until the late 1970s, with the continuous improvement of people’s living standards and the gradual improvement of sanitary conditions, the incidence of biliary ascariasis began to show a significant downward trend. 4, gray nail nail fungus (onychomycosis) is caused by dermatophytes, yeast and non-dermatophytic filamentous fungi (mold) infection of the finger (toe) nail. Nail disease caused by dermatophytes infecting the nail plate alone is called onychomycosis (tinea unguium). Tinea unguium is mostly spread directly from tinea pedis, while tinea nail infections may be spread by tinea cruris or by direct contact with tinea cruris from scratching other parts of the body. Tinea unguium is commonly known as “gray nail”, and in Chinese medicine it is called chicken claw wind and oil gray nail. 5. Parasitic arthritis Parasitic diseases are endemic to many developing countries and are also found in developed countries. The clinical manifestations of parasitic infections vary, with some patients being asymptomatic, but others showing a variety of clinical manifestations. Parasitic arthritis, a bone and joint disease due to parasitic infection is less common in clinical practice. To date, there are at least 20 species of parasites that can directly or indirectly damage the human bone and joint system. They either cause lesions in bone tissue, joints and bone marrow, prevent normal bone growth, or cause skeletal deformities in fetuses. The incidence of joint involvement in parasitic infections is very low. Diagnosis relies on: ① a history of residence or travel in the infected area; ② clinical manifestations of infection caused by parasitic invasion of the intestine or tissues; ③ acute or chronic onset, mono- or polyarthritis; ④ failure to respond to treatment with antibacterial inflammatory therapy; ⑤ elimination of joint symptoms after eradication of the parasite. Joint inflammation can be caused directly by parasites residing in the muscles surrounding the joints, by metabolites of the parasites, or by an immune response.