ABSTRACT
Medium vessel vasculitis involves the main visceral arteries (and veins) and their initial branches and cutaneous vessels that contain a tunica media made of concentric layers of smooth muscles. The medium vessel vasculitides include polyarteritis nodosa and Kawasaki disease. Medium vessel vasculitis may only involve skin vasculature or manifest as a systemic vasculitis, and it is usually the latter that requires emergency management in an intensive care setting due to the occurrence of acute pulmonary insufficiency, renal or cardiac failure, or neurological and gastrointestinal complications. Cutaneous polyarteritis nodosa (PAN) represents a skin-limited disease and accounts for 10% of cases. The most frequent features are tender subcutaneous nodules, livedo reticularis, and ulcers. PAN usually presents with constitutional symptoms of fever, malaise, myalgia, and weight loss along with features of multisystem involvement. The presentation varies widely: it may run an indolent course or lead to abrupt onset of life-threatening complications. Kawasaki disease should be suspected in any child presenting with unexplained and prolonged fever associated with cutaneous changes. The cutaneous exanthem, often manifesting as a diffusely morbilliform rash, occurs in greater than 80% of patients. The rash usually begins within 5 days of the onset of fever. Involvement of the trunk and extremities with desquamation in the groin area is an early and characteristic finding
