Mucocutaneous rashes are most often seen in syphilis and occur on the chest, abdomen, flanks and back of the trunk, but rarely on the face. Syphilitic pustules can occur in weak and malnourished patients, often with high fever and systemic symptoms. Mucocutaneous rash needs to be distinguished from the following diseases: pityriasis rosea: pityriasis rosea (Pityriasisrosea) is a common inflammatory skin disease that occurs on the trunk and proximal extremities in variable size and number of rose-colored patches with sugar-like scales and self-induced pruritus. It is self-limiting, usually lasting 6 to 8 weeks and healing on its own. This disease is similar to “wind ringworm” recorded in the literature of Chinese medicine. Rose furfur: Rose furfur (Pityriasisrosea) is a common inflammatory skin disease, which occurs on the trunk and proximal extremities of varying sizes, the number of variable rose-colored patches, on which there are sugar-like scales, conscious itching. It is self-limiting, usually lasting 6 to 8 weeks and healing on its own. The disease is similar to “tinea fungus” recorded in the literature of Chinese medicine. Pemphigus foliaceus: Generally there is no conscious symptom, but it can be itchy when working, sunbathing or sweating a lot. It is more common in men and occurs in winter and summer. The rash occurs in areas with sebaceous glands, such as the trunk, neck, upper arms, abdomen and face, and may also involve the buttocks, armpits and groin. The skin lesions are round or round-like rashes of corn, soybean or bean size, reflective and covered with very thin furred scales. In most patients, the lesions are diffuse and symmetrical, with the patches flattened or raised against the skin, and the boundaries are clear. Psoriasis: psoriasis, commonly known as “psoriasis”, is a common, easily recurring chronic inflammatory skin disease, characterized by red papules or plaques covered with multiple layers of silvery white scales. It is most common in young adults, more common in men than women, and more common in the north than in the south, and is more likely to develop or worsen in spring and winter, and to remit in summer and fall. The etiology and pathogenesis of the disease are not completely clear, and studies have found that the onset of the disease is related to genetic factors, streptococcal infection, abnormal immune function, metabolic disorders and endocrine changes. There are four clinical types: the common type, the pustular type, the erythrodermic type and the arthritic type. Psoriasis vulgaris is the most common and the disease is mild. The disease has a chronic course and is prone to recurrence after cure.