Most biopsies of
cutaneous vasculitis will exhibit a small vessel neutrophilic
vasculitis [
leukocytoclastic vasculitis (LCV)] that is associated with
immune complexes on direct immunofluorescence examination or, less commonly, antineutrophilic cytoplasmic
antibodies (
ANCA) by indirect immunofluorescence testing. Is in uncommon for skin biopsy to reveal solely a neutrophilic
arteritis signifying the presence of cutaneous
polyarteritis nodosa or, if accompanied by significant lobular
panniculitis, nodular
vasculitis/
erythema induratum. In other cases, cutaneous vascular damage (fibrinoid
necrosis, muscular vessel wall disruption, or
endarteritis obliterans) will be mediated by a nonneutrophilic inflammatory infiltrate. Eosinophilic
vasculitis can be a primary (idiopathic) process that overlaps with
hypereosinophilic syndrome, or it can be a secondary
vasculitis associated with
connective tissue disease or parasite infestation. Authentic cutaneous granulomatous
vasculitis (versus
vasculitis with extravascular
granulomas) can represent a cutaneous manifestation of
giant cell arteritis, an eruption secondary to systemic disease such as
Crohn's disease or
sarcoidosis, or a localized disorder, often a post-
herpes zoster (HZ) phenomenon. Lymphocytic
vasculitis is a histologic reaction pattern that correlates with broad clinical differential diagnosis, which includes
connective tissue disease - mostly
systemic lupus erythematosus (SLE), endothelial
infection by Rickettsia and viruses, idiopathic lichenoid
dermatoses such as
perniosis or ulcerative necrotic
Mucha-Habermann disease, and angiocentric
cutaneous T-cell lymphomas. Skin biopsy extending into the subcutis, identifying the dominant inflammatory cell and caliber of vessels affected, extravascular histologic clues such as presence of lichenoid
dermatitis or
panniculitis, and correlation with clinical data allows for accurate diagnosis of these uncommon vasculitic entities.