Palpable
purpura tends to indicate involvement of small vessel
vasculitis in the upper dermis.
Livedo racemosa, nodular lesion and skin ulceration are indicative of involvement of small to medium-sized vessel
vasculitis in the lower dermis to subcutaneous fat. We set out to establish a new algorithm (KAWAKAMI algorithm) for primary
cutaneous vasculitis based on the Chapel Hill Consensus Conference classification and our research results, and apply to the diagnosis. The first step is to measure serum
antineutrophil cytoplasmic antibodies (
ANCA) levels. If
myeloperoxidase-
ANCA is positive,
Churg-Strauss syndrome or
microscopic polyangiitis can be suspected, and if the patient is positive for
proteinase 3-ANCA,
Wegener's granulomatosis is most likely. Next, if
cryoglobulin is positive, cryoglobulinemic
vasculitis should be suspected. Third, if direct immunofluorescence of the skin biopsy specimen reveals
immunoglobulin A deposition within the affected vessels, Henoch-Schönlein
purpura is indicated. Finally, the presence of anti-
phosphatidylserine-
prothrombin complex
antibodies and/or
lupus anticoagulant and histopathological necrotizing
vasculitis in the upper to middle dermis (
leukocytoclastic vasculitis) indicates
cutaneous leukocytoclastic angiitis, whereas if necrotizing
vasculitis exists in the lower dermis and/or is associated with the subcutaneous fat, cutaneous
polyarteritis nodosa is indicated. The KAWAKAMI algorithm may allow us to refine our earlier diagnostic strategies and allow for efficacious treatment of primary
cutaneous vasculitis. In cutaneous
polyarteritis nodosa,
warfarin or
clopidogrel therapies should be administrated, and in cases that have associated active inflammatory lesions,
corticosteroids or
mizoribine (
mycophenolate mofetil)
therapy should be added. We further propose prophylactic treatment of renal complications in patients with Henoch-Schönlein
purpura.