Mastocytosis, also known as pigmentary urticaria, was first reported by Nettleship in 1869. Clonal studies and mutational analysis suggest that at least some adult mastocytic cases are due to neoplastic hyperplasia of mast cells, whereas in children mastocytosis is a cytokine-induced hyperplasia. The disease develops before the first 6 months of life in about 1/2 of patients and occurs before puberty in 1/4. Skin lesions include macules, papules, nodules, plaques, blisters or macules. Occasionally, capillary dilation, petechiae or petechiae are seen. Initially resembling urticaria but not fading, the lesions persist and gradually take on a buckskin or slate color. The lesions are persistent and gradually take on a buckskin or slate color. The lesions often become erythematous and peri-erythematous (Darier’s sign) when the skin is scratched or rubbed with force. The lesions are often slightly elevated and the nodules may be firm, disseminated or fused with each other and have a light brown waxy appearance. Clinically 1/3 to 1/2 of patients have positive skin mydriasis when the normal skin is scratched. After taking histamine-releasing agents such as alcohol, morphine or codeine or after extensive rubbing, severe symptoms such as pruritus, diffuse flushing all over the body, and even deficiency, headache, bradycardia, hypotension with fatigue, loss of appetite, diarrhea and joint pain can occur due to the massive release of histamine. The disease can be clinically divided into the following types: 1. Isolated mast cell tumors Isolated nodules appear at birth or in the first week after birth. Dry papules or elevated round or ovoid plaques up to 20 mm in diameter. the surface is smooth or slightly warty (orange peel-like). Oedema, pemphigus, blisters and even blisters are seen on the damage. Occasionally, several mast cell tumors may occur. Most isolated mast cell tumors resolve spontaneously by age 10. 2. Childhood generalized mastocytosis, usually seen in the first week of life, presents as a rose-colored pruritic, wind-blown, mildly pigmented rash, papule or nodule. The lesions are ovoid or round with a small diameter of 5 to 15 mm, may fuse with each other, and are yellowish to maroon in color. Blistering or maculopapular formation is common in the early stages of the disease. The lesions usually resolve spontaneously over several years before puberty, but they have been known to persist into adulthood. Systemic damage may occur, but malignant systemic disease is extremely rare. 3. Adult-onset generalized mastocytic hyperplasia is most commonly characterized by pale brown papules and nodules with typical wind clusters, spreading throughout the body, especially on the upper arms, lower legs and trunk. 4. Pseudoxanthomatous mastocytic hyperplasia A large number of yellowish nodules of 1 to 2 cm in diameter appear at birth. The spleen is large and appears erythematous rather than windy when rubbed. Histopathology shows dense mast cell infiltration. 5. Diffuse cutaneous mast cell hyperplasia The entire skin is diffusely involved and thickened, with a peculiar orange color due to mast cell infiltration. The skin infiltrates with a raw dough-like toughness, and mossiness is seen. 6, erythrodermic mast cell hyperplasia is a generalized erythrodermic disease, the skin is granular outward leather-like appearance. The entire surface of the skin can be produced by the wind mass. 7, persistent eruptive macular capillary dilation is a persistent pigmented asymptomatic macular eruption with a dry reddish tinge and rare or inconspicuous capillary dilation. This type is a benign disease, most cases are only cosmetic problems, bone damage and peptic ulcers can occur. Darier’s disease may be absent. 8, systemic mast cell hyperplasia Mast cell hyperplasia occurs not only in the skin, but can also involve the lymph nodes, gastrointestinal system, bones, heart, blood, liver and spleen. The disease passes progressively or remains quiescent. The skin lesions are mostly nodular, the bone damage is usually asymptomatic, radiographs show radiolucent and radiolucent areas, the bone damage is usually quiescent, and non-progressive mast cell leukemia rarely occurs. The gastrointestinal tract may show characteristic mucosal lesions and abdominal pain, nausea and vomiting are common. Systemic mastocytosis occurs most often in adults, but approximately 10% of patients with juvenile disseminated disease have systemic involvement. It can also cause organ dysfunction due to secondary hypereosinophilic syndrome. The release of large amounts of histamine from mast cells causes systemic reactions, including flushing. Vomiting, nosebleeds, bloody stools and petechiae may occur due to increased plasma heparin. Anemia, leukopenia and thrombocytopenia, increased prothrombin time, and increased 24h urinary histamine may occur in 60% of patients. Malignant mastocytosis can occur when large numbers of mast cells infiltrate multiple organs and disrupt normal function. In rare cases, the cutaneous visceral form can be fatal. Extensive systemic infiltration can also cause death. 9, familial pemphigoid hyperpigmentation Familial pemphigoid hyperpigmentation is rare. It is inherited in an autosomal dominant fashion. The prognosis and course of the disease depends largely on the age of onset of the disease and its type. Mast cell hyperplasia with a single lesion in children usually resolves within a few years, and usually resolves spontaneously at about 10 years of age. There are also cases that persist into adulthood, and a few patients may develop a widespread rash. The prognosis is best for widespread pigmentary urticaria in young children, with more than half of cases resolving spontaneously in adolescence and a slightly worse prognosis in later-onset cases, and rarely in adults, but it is benign and only rarely malignant. The presence of blisters does not affect the prognosis. A small number of patients with either infantile or pediatric onset can develop systemic lesions, but death occurs in only a very few cases.