Page 161 - The Vasculitides, Volume 1: General Considerations and Systemic Vasculitis

Nomenclature and Pathologic Features of Vasculitides 137

HUV is characterized by recurrent episodes of urticaria with underlying leukocytoclastic
vasculitis that causes hemorrhage into the lesions [24]. Skin manifestations include painful,
tender, burning or pruritic lesions that persist for greater than 24 hours, often with central or
diffuse areas of hemorrhage. HUV can be isolated or associated with autoimmune diseases
(including lupus), infections, drug reactions, or neoplasms. Proteinuria and hematuria occur in
20-30% of patients and the underlying glomerular lesion usually has a membranoproliferative
pattern, but other proliferative and focal necrotizing lesions may occur. Glomeruli and dermal
vessels have granular deposits of IgG, IgA, IgM, C3 and C1q, which resembles the “full
house” immunostaining seen in SLE.

IgG autoantibodies to the collagen-like region of C1q (anti-C1q) are usually present and
may play a role in pathogenesis [25]. The hypocomplementemia appears to be secondary to
classical pathway activation with reduced C1, C2, C4, and C3. The marked localized edema
(urticarial) may be a manifestation of enhanced complement mediated vascular permeability
resulting from an effect of anti-C1q antibodies on complement activation.

Variable Vessel Vasculitis

VVV is a category of vasculitis that was not included in the CHCC 1994 nomenclature
system [2]. The CHCC 2012 defines VVV as vasculitis with no predominant type of vessel
involved that can affect vessels of any size (small, medium, and large) and type (arteries,
veins, and capillaries). Two protean vasculitides are included, BD and CS [1]. Although these
disease are rare and vasculitis caused by them is even rarer, they were included for
completeness and so that they will be considered in the differential diagnosis of patients with
vasculitis.

BD is clinically characterized by recurrent oral and/or genital aphthous ulcers
accompanied by cutaneous, ocular, articular, gastrointestinal, and central nervous system
(CNS) inflammatory lesions. Small vessel vasculitis, thromboangiitis, thrombosis, arteritis
and arterial aneurysms may occur. The associated vasculitis can involves both arteries and
veins of all sizes for example the aorta and large arteries to small mucosal and cutaneous
veins, venules, arterioles and arteries (Figure 10) [27-29]. The aorta and other large arteries
such as the pulmonary arteries may demonstrate transmural neutrophil-rich inflammation
resulting in aneurysm formation, and small vessels have leukocytoclastic angiitis. Aortitis and
arteritis can result in aneurysm formation, vascular stenoses and occlusions. Arterial
complications are less common than venous lesions, which include phlebitis and thrombosis.
A variant called „vasculo-Behçet disease? has prominent vascular complications including
vasculitis, thrombosis, stenoses, occlusions, and aneurysms.

CS is clinically characterized by ocular inflammatory lesions, including interstitial
keratitis, uveitis, and episcleritis, and inner ear disease, including sensorineural hearing loss
and vestibular dysfunction [30-32]. The associated vasculitis which occurs in approximately
15% of affected patients, includes arteritis of small, medium or large arteries; aortitis, aortic
aneurysms, and aortic and mitral valvulitis [1]. Involved vessels can have transmural
infiltration of neutrophils in the acute phase.

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