MILAN – , Robert Micheletti, MD, said at the World Congress of Dermatology.
Dr. Robert Micheletti
In granulomatous vasculitis, histiocytes and giant cells can play a significant role, explained Dr. Micheletti, director of the cutaneous vasculitis clinic at the University of Pennsylvania, Philadelphia. The condition may be secondary to an autoimmune disease such as lupus erythematosus or RA; a granulomatous disease such as Crohn’s disease or sarcoidosis; infections such as tuberculosis, a fungal disease, or herpes or zoster viruses, or lymphoma, Dr. Micheletti said.
However, a primary systemic vasculitis such as granulomatosis with polyangiitis (GPA; formerly known as Wegener’s polyangiitis) or eosinophilic granulomatosis with polyangiitis (EGPA; also known as Churg-Strauss vasculitis), giant cell arteritis, or Takayasu arteritis may also be responsible, he said. Occasionally, the culprit can also be a drug-induced vasculitis.
The physical examination gives clues to the size of involved vessels, which in turn helps to classify the vasculitis, Dr. Micheletti said.
When vasculitis affects small vessels, the skin findings will be palpable purpura, urticarial papules, vesicles, and petechiae, he said, adding that “The small vessel involvement accounts for the small size of the lesions, and complement cascade and inflammation account for the palpability of the lesions and the symptomatology.” As red blood cells extravasate from the affected vessels, nonblanching purpura develop, and gravity’s effect on the deposition of immune complex material dictates how lesions are distributed.
“Manifestations more typical of medium vessel vasculitis include subcutaneous nodules, livedo reticularis, retiform purpura, larger hemorrhagic bullae, and more significant ulceration and necrosis,” he said. “If such lesions are seen, suspect medium-vessel vasculitis or vasculitis overlapping small and medium vessels.” Cutaneous or systemic polyarteritis nodosa, antineutrophilic cytoplasmic autoantibody (ANCA)–associated vasculitis, and cryoglobulinemic vasculitis are examples, he added.
The particularities of renal manifestations of vasculitis also offer clues to the vessels involved. When a vasculitis patient has glomerulonephritis, suspect small-vessel involvement, Dr. Micheletti said. However, vasculitis affecting medium-sized vessels will cause renovascular hypertension and, potentially renal arterial aneurysms.
Nerves are typically spared in small-vessel vasculitis, while wrist or foot drop can be seen in mononeuritis multiplex.
Recently, the Diagnostic and Classification Criteria in Vasculitis Study (DCVAS) looked at more than 6,800 patients at over 130 sites around the world, proposing new classification criteria for ANCA-associated vasculitis (AAV) and large-vessel vasculitis. The study found that skin findings are common in AAV, with 30%-50% of cases presenting initially with skin lesions. Petechiae and/or purpura are the most common of the skin manifestations, he said. By contrast, for EGPA, allergic and nonspecific findings were the most common findings.
Although skin biopsy can confirm the diagnosis in up to 94% of AAV cases, it’s underutilized and performed in less than half (24%-44%) of cases, Dr. Micheletti said. The study’s findings “demonstrate the importance of a good skin exam, as well as its utility for diagnosis” of vasculitis, he said.
An additional finding form the DCVAS study was that skin lesions can give clues to severity of vasculitis: “Among 1,184 patients with ANCA-associated vasculitis, those with cutaneous involvement were more likely to have systemic manifestations of disease, more likely to have such severe manifestations as glomerulonephritis, alveolar hemorrhage, and mononeuritis,” said Dr. Micheletti, with a hazard ratio of 2.0 among those individuals who had EGPA or GPA.
“Skin findings have diagnostic and, potentially, prognostic importance,” he said. “Use the physician exam and your clinical acumen to your advantage,” but always confirm vasculitis with a biopsy. “Clinicopathologic correlation is key.” A simple urinalysis will screen for renal involvement, and is of “paramount importance,” he added.
Dr. Micheletti reported that he had no relevant disclosures.