It is not clear and may be related to three factors: infection, genetics, and immunity. Mental stimulation, dietary factors and unhygienic habits can induce exacerbation of the disease. There is no specific treatment available, and neither drugs nor surgery can cure the disease; supportive therapy and symptomatic treatment are generally used. The disease was first described by Crohn et al. in 1932 and was therefore named Crohn’s disease (formerly known as Crohn’s disease) by the World Health Organization. It used to be called “restricted enteritis” and “granulomatous enteritis”. The disease is most common in young people, and lesions can occur anywhere in the digestive tract (from the mouth to the anus), but are most common in the terminal ileum and the right hemicolectum. The cause of Crohn’s disease is still unknown, and the causative factors were previously thought to be infectious, genetic, and immune factors. Nowadays, some scholars believe that inflammatory bowel disease occurs due to endogenous bacteria. The lesions can involve all parts of the GI tract from the mouth to the anus, but the ileum and colon are the most frequent. Metastatic lesions of the skin can also occur, manifesting near the perineum, groin, and post-surgical enterocutaneous fistulae, primarily as skin ulcers, with granulomatous inflammation visible on skin biopsy, and other skin lesions such as gangrenous pyoderma, erythema nodosum, somatic eczema, and oral and external genital ulcers.