Page 400 - The Vasculitides, Volume 1: General Considerations and Systemic Vasculitis

374 Rami N. Al-Rohil and J. Andew Carlson

evaluation of vasculitides are that the characteristics of the initial insult may be lost during the
process of repair leading to the transformation from active, acute inflammatory lesions into
older, often sclerotic lesions wherein T-cells and macrophages predominate and
neovascularization transpire to compensate for the ischemic insult. Nonetheless, the type of
inflammatory cell mediating vessel damage and vessel size affected roughly correlates with
pathogenic mechanisms.

Clinical Presentation

Systemic symptoms of fever, malaise, weight loss, arthritis, and arthralgia will
accompany cutaneous vasculitides. Vasculitic lesions may affect dependent sites of the legs
especially under tight fitting clothes, less so along the arms, trunk, head and neck signifying
more severe disease or coexisting systemic vasculitis [14]. Cutaneous vasculitis commonly
manifests as palpable purpura and infiltrated erythema indicating dermal small vessel
vasculitis (SVV); less frequently as nodular erythema, livedo racemosa, punched-out ulcers,
or digital gangrene due to muscular-vessel vasculitis. The type of cutaneous lesions closely
correlates with the size of vessel affected by vasculitis. Sparse superficial perivascular
neutrophilic infiltrates associated with nuclear debris and extravasated red blood cells result
in urticarial papules and plaques, which last >24 h, burn rather than itch, and resolve with
residual pigmentation. Predominantly small vessel vasculitis (SVV) results in purpuric
macules and infiltrated erythema, whereas deeper dermal SVV correlate with palpable
purpura and vesiculobullous lesions. Ulcers, nodules, pitted scars, or livedo reticularis are
associated with arterial muscular vessel involvement, which will be located at the dermal–
subcutis interface or within the subcutis [4].

Laboratory Evaluation

Histopathologic Studies

Table 3 shows the histologic criteria for the diagnosis of cutaneous vasculitis. The
diagnosis of cutaneous vasculitis of small- and medium-sized muscular vessels is established
by biopsy and examination of hematoxylin and eosin (H& E)-stained sections followed by
direct immunofluourescent (DIF) studies. Fibrinoid necrosis is comprised of fibrin deposition
within and around the vessel wall and is a feature of nearly all early vasculitic lesions. It
results from the accumulation of plasma proteins, including coagulation factors that are
converted to fibrin, at sites of vessel wall destruction. Inflammatory infiltrates within and
around the walls of vessels accompanied by fibrin deposition (Figure 4) may be accompanied
by endothelial damage in the form of endothelial swelling and shrinkage due to apoptosis and
sloughing (Figure 5).

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