Extensive erythematous infiltrative damage with desquamation is known as erythroderma. Erythroderma is a serious skin disease with systemic symptoms of widespread redness, swelling, and flaking of the skin. Erythroderma occurs before malignant tumors and is associated with various lymphomas, especially Hodgkin’s disease, but also with adenocarcinoma and lung cancer. Erythrodermic disease should be diagnosed not only from symptoms, but also from toxic epidermal necrolysis relaxans type of drug rash and deciduous aspergillosis. Differential diagnosis of extensive erythematous infiltrative damage with desquamation: 1. toxic epidermolysis bullosa drug rash Although there is high fever, extensive large erythematous and maculopapular lesions, the main lesion is a large blister on the base of the erythematous plaque, the wall of the blister is relaxed, and the Nee’s sign is positive. 2. deciduous aspergillosis Large blisters on normal skin with positive Ney’s sign, usually without mucosal damage. It can be differentiated based on histopathology. Under normal conditions, the body maintains a dynamic balance between heat production and heat dissipation processes. In patients with erysipelas, the absorption of toxins and the malfunction of skin heat dissipation can cause different degrees of fever, with most patients having a body temperature of about 38°C to 39°C. If high fever and toxic symptoms are evident, co-infection should be considered. When erythroderma appears, it should be given enough attention and treated actively.