Corns are a common dermatological disease, mainly caused by friction and compression. They typically appear as small, round, hard lumps that are painful to press with the hand. They often occur on the soles of the feet or toes. Corns are usually caused by wearing shoes that are too tight or by standing for prolonged periods, which irritates the skin of the feet over time. Once corns develop, they must be treated promptly; otherwise, the pain may affect walking or make it impossible to walk.