The worst skin diseases include diseases caused by abnormalities in the autoimmune system, postherpetic neuralgia, neurodermatitis, psoriasis and other types, as follows: 1, due to abnormalities in the autoimmune system: herpetic aspergillosis, common aspergillosis and autoimmune diseases such as lupus erythematosus, dermatomyositis, systemic scleroderma; 2, postherpetic neuralgia: can be long-lasting, and the general treatment cycle 3, eczema, neurodermatitis, psoriasis: can be lingering, which also includes arthritic psoriasis, pustular psoriasis, erythrodermic psoriasis, these three types of psoriasis is very difficult to treat. In addition, erythrodermic disease is also a skin disease whose cause is not easily defined, and it is relatively difficult to treat.