The disease is a group of chronic skin diseases due to capillary dilation causing petechiae and iron-containing heme deposits, including progressive pigmented purpuric dermatosis, pigmented purpuric lichenoid dermatosis) and capillary dilated cyclic purpura (purpura annularis telangiectosis). These three diseases are closely related, with similar clinical manifestations and histopathology. The etiology and pathogenesis of the disease is unknown, it is capillary vasculitis, gravity and increased venous pressure are important triggers. It is thought to be a metaplastic disease caused by local infection or poisoning. Capillary dilated annular purpura may be the skin manifestation of systemic diseases, but none of them have been confirmed. The first is a cluster of pinpoint-sized red petechiae, which gradually expand and fuse into patches, and the lesions become brownish yellow and tan due to iron-containing heme deposits, with the appearance of peppercorn-like dots. New petechiae keep appearing around the old lesions. Mild pruritus is observed. The lesions are usually found on the extensor side of both calves and around the ankles. The course of the disease is chronic and can be self-healing. 2, pigmented purpura mossy dermatitis: also known as Gougerot-Blum disease, mostly seen in men aged 40-60 years old, lesions are small red or rust-colored mossy papules, petechiae, can be fused into plaques, often accompanied by pruritus. The lesions are small red or rust-colored mossy papules and petechiae, which may fuse into plaques, often with pruritus. 3, capillary dilated annular purpura: also known as Majocchi disease, young people and adults are common, initially as a purple-red annular rash, 1 ~ 3cm in diameter, the rash can be seen in the capillary dilation and pepper-like petechiae, the lesions can gradually expand, due to iron-containing heme deposition and become purple, yellow or brown, the edge of the new petechiae can appear, forming a ring, arc or concentric circle-like damage. The lesions are more common on the lower legs and gradually expand to the thighs, and can spread to the trunk and buttocks. Pathological changes] The pathological changes of the three diseases are basically similar. The superficial capillary endothelium of the dermis is swollen, surrounded by lymphocyte and histiocyte infiltration, erythrocyte spillover, and iron-containing heme deposits. Diagnosis and Differential Diagnosis】 The diagnosis is easy according to the clinical manifestations. It needs to be differentiated from bruising dermatitis, allergic purpura, hyperglobulinemic purpura, etc. Treatment】 No special treatment, patients need to reduce standing or walking, pay attention to elevate the lower limbs.