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| Fig. 15.4 Cutaneous polyarteritis nodosa. A, Characteristic linear erythematous lesion. Note the Y-shaped bifurcation. B, Reticulated hyperpigmented lesion with an associated ulceration. (Courtesy of James E. Fitzpatrick, MD.) |
As the name implies, this is polyarteritis nodosa that is essentially confined to the skin, although it is not uncommon for patients to experience fever, arthralgias, and mysositis. The cutaneous lesions are most commonly located on the lower extremity and manifest as painful subcutaneous nodules that may resemble erythema nodosum, or demonstrate a characteristic “star-burst” appearance (Fig. 15-4). This diagnostic appearance is due the arteritis following the bifurcations of the small- and medium-sized arteries. Secondary changes that may be present include associated livedo reticularis and ulceration. In contrast to systemic polyarteritis nodosa, peripheral gangrene is not seen. Laboratory studies are generally normal except for variable mild leukocytosis and an elevated erythrocyte sedimentation rates (ESR).
