tailieunhanh - Clinical Dermatology - part 5

Đây có thể xuất hiện tại các địa điểm kỳ lạ, chẳng hạn như đùi, mông hoặc lưng của bắp chân. Các loại phổ biến nhất của panniculitis lở loét panniculitis lupus, panniculitis tuyến tụy và ban đỏ induratum (p. 130). Ác tính loét. Những người gây ra bởi ung thư biểu mô tế bào vảy | 142 CHAPTER 11 Panniculitic ulcers. These may appear at odd sites such as the thighs buttocks or backs of the calves. The most common types of panniculitis that ulcerate are lupus panniculitis pancreatic panniculitis and erythema induratum p. 130 . Malignant ulcers. Those caused by a squamous cell carcinoma p. 267 are the most common but both malignant melanomas p. 268 and basal cell carcinomas p. 265 can present as flat lesions which expand crust and ulcerate. Furthermore squamous cell carcinoma can arise in any longstanding ulcer whatever its cause. Pyoderma gangrenosum p. 292 . These large and rapidly spreading ulcers may be circular or polycyclic and have a blue indurated undermined or pustular margin. Pyoderma gangrenosum may complicate rheumatoid arthritis Crohn s disease ulcerative colitis or blood dyscrasias. Investigations Most chronic leg ulcers are venous but other causes should be considered if the signs are atypical. In patients with venous ulcers a search for contributory factors such as obesity peripheral artery disease cardiac failure or arthritis is always worthwhile. Investigations should include the following. Urine test for sugar. Full blood count to detect anaemia which will delay healing. Swabbing for pathogens see Bacterial superinfection above . Venography colour flow duplex scanning and the measurement of ambulatory venous pressure help to detect surgically remediable causes of venous incompetence. Doppler ultrasound may help to assess arterial circulation when atherosclerosis is likely. It seldom helps if the dorsalis pedis or posterior tibial pulses can easily be felt. If the maximal systolic ankle pressure divided by the systolic brachial pressure ankle brachial pressure index is greater than the ulcer is unlikely to be caused by arterial disease. Cardiac evaluation for congestive failure. Treatment Venous ulcers will not heal if the leg remains swollen and the patient chair-bound. Pressure bandages take priority over other measures