In 23 cases, biopsy specimens showed acute inflammatory periarteritis. Noteworthy findings were the absence of systemic disease and the chronic relapsing course. No patient died of his disease, but five patients had intermittent lesions for 20 years or more. Nodules, livedo reticularis, and ulcers were the characteristic lesions found. Focal livedo reticularis, with a "star-burst" appearance, was found in 12 cases. Although fever and arthralgia were not uncommon, many patients were completely asymptomatic. All patients had elevated erythrocyte sedimentation rates at some time during the course of the disease; but other laboratory findings were essentially normal. In four of the eight patients, the electromyogram showed specific evidence of neuropathy or focal myositis (or both) limited to the involved extremity. The muscular vessels of the skin can be the principal site of vascular inflammation and will present a characteristic syndrome—that of cutaneous periarteritis nodosa.
Diaz-Perez JL, Winkelmann RK. Cutaneous Periarteritis Nodosa. Arch Dermatol. 1974;110(3):407-414. doi:10.1001/archderm.1974.01630090045009