Generally speaking, large nail protrusion arc may be sick, mostly caused by nail malnutrition, nail fungal disease, trauma, psoriasis nail and other diseases. 1. Nail malnutrition: Insufficient intake of vitamins due to malnutrition, gastrointestinal diseases, etc. will have an impact on the growth of nails, which may lead to nail bulging. It is recommended to maintain balanced nutrition and eat more green fruits and vegetables to supplement vitamins. 2. Nail fungus disease: Nail fungus disease, also called gray nail, is a disease caused by fungal infection. The fungus invades the nail plate and causes the nail to become yellow, thickened and easily broken and raised. You can use antifungal drugs such as ketoconazole ointment, pay attention to hand hygiene, do not share towels with others. 3. Trauma: Nails are hit or extruded, and if they can’t be repaired, there will be nail protrusion in the later stage. 4. Psoriasis nails: related to psoriasis invading the nail matrix and nail bed, psoriasis nails can lead to thickening under the nails, nails with concave points or appear raised. Nail protrusion arc also seen in other causes, it is recommended to timely visit the hospital, and combined with the doctor’s recommendations for treatment, so as not to delay the condition.