常有中老年朋友偶然发现小腿有成片的红色淤点，用手指按压不褪色，久之还可出现黑斑，以致红黑斑点相间，此消彼长，但又不痒不痛。此症常被误诊为过敏性紫癜或血小板减少性紫癜，但详细检查找不出致敏原，血小板也不减少。原来，这是一种色素性紫癜性皮炎。该症以４０～６０ Often middle-aged friends occasionally found that the calf has a piece of red bruising point, press with your fingers does not fade, long time there may be spots, resulting in red and black spots and white, the counteraction of each other, but not itch does not hurt. This disease is often misdiagnosed as anaphylactoid purpura or thrombocytopenic purpura, but a detailed examination can not find allergens, platelets do not reduce. It turned out that this is a pigmented purpura dermatitis. The disease to 40 to 60