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Chapter 054. Skin Manifestations of Internal Disease (Part 27)

Also associated with systemic diseases. b Reviewed in section on Purpura. cReviewed in section on Papulonodular Skin Lesions. d Favors plantar surface of the foot. Note: TEN, toxic epidermal necrolysis. Livedoid vasculopathy (livedoid vasculitis; atrophie blanche) represents a combination of a vasculopathy plus intravascular thrombosis. Purpuric lesions and livedo reticularis are found in association with painful ulcerations of the lower extremities. These ulcers are often slow to heal, but when they do, irregularly shaped white scars are formed. The majority of cases are secondary to venous hypertension, but possible underlying illnesses include cryofibrinogenemia and disorders of hypercoagulability, e.g., the antiphospholipid syndrome (Chaps. 111 and 313). . | Chapter 054. Skin Manifestations of Internal Disease Part 27 Also associated with systemic diseases. Reviewed in section on Purpura. cReviewed in section on Papulonodular Skin Lesions. dFavors plantar surface of the foot. Note TEN toxic epidermal necrolysis. Livedoid vasculopathy livedoid vasculitis atrophie blanche represents a combination of a vasculopathy plus intravascular thrombosis. Purpuric lesions and livedo reticularis are found in association with painful ulcerations of the lower extremities. These ulcers are often slow to heal but when they do irregularly shaped white scars are formed. The majority of cases are secondary to venous hypertension but possible underlying illnesses include cryofibrinogenemia and disorders of hypercoagulability e.g. the antiphospholipid syndrome Chaps. 111 and 313 . In pyoderma gangrenosum the border of the ulcers has a characteristic appearance of an undermined necrotic violaceous edge and a peripheral erythematous halo. The ulcers often begin as pustules that then expand rather rapidly to a size as large as 20 cm. Although these lesions are most commonly found on the lower extremities they can arise anywhere on the surface of the body including sites of trauma pathergy . An estimated 30-50 of cases are idiopathic and the most common associated disorders are ulcerative colitis and Crohn s disease. Less commonly pyoderma gangrenosum is associated with seropositive rheumatoid arthritis acute and chronic myelogenous leukemia hairy cell leukemia and myelofibrosis. Additional findings in these patients even those with idiopathic disease are cutaneous anergy and a monoclonal gammopathy usually IgA. Because the histology of pyoderma gangrenosum may be nonspecific dermal infiltrate of neutrophils when in untreated state the diagnosis is usually made clinically and includes excluding less common causes of similar-appearing ulcers such as necrotizing vasculitis Meleney s ulcer synergistic infection at a site of trauma or surgery .