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CHAPTER 122 ing), is important in assessing the lesion. In the absence of accompa-
The shape of a purpuric lesion, either round or retiform (branch-
THE VASCULAR PURPURAS nying inflammation, retiform purpuric lesions suggest small vessel
occlusion. A retiform, inflammatory purpuric lesion supports the diag-
nosis of vasculitis as a result of immunoglobulin (Ig) complex for-
mation. Small, focal areas of hemorrhage are referred to as petechiae
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Doru T. Alexandrescu and Marcel Levi (≤4 mm). Larger lesions are referred to as intermediate or midsize pur-
pura (>4 mm, <1 cm) or ecchymosis (≥1 cm). 3
Purpuric lesions frequently appear purple; however, they can
SUMMARY take on a variety of colors, according to the age of the lesion and
the oxygen saturation of the hemoglobin in the extravasated blood.
Ecchymosis usually starts as blue or purple, evolves to a greenish
Purpura, the clinical manifestation of blood extravasation into mucosa or skin, brown (a mixture of blue and yellow), and ultimately changes with
results from various conditions, including rheumatologic, infectious, derma- variable speed to yellow as hemoglobin degrades to bilirubin. These
4
tologic, traumatic, and hematologic disorders. This chapter does not detail examples of hemorrhage into the dermis must be distinguished from
purpura resulting from quantitative or functional defects in hemostasis and telangiectasia, which are vascular anomalies that blanch with pressure
coagulation, such as deficiencies of platelets or coagulation factors; these (see Fig. 122–1). Tables 122–1 through 122–3 classify the etiologies
causes are discussed in other chapters (e.g., thrombocytopenia in Chap. 117; for purpura discussed in this chapter.
coagulation factor deficiencies in Chaps. 123 and 124).
The differential diagnosis of the disparate causes of noncoagulopathic PALPABLE NONINFLAMMATORY
purpura is best approached by stratifying purpura into three types of lesions: PURPURIC LESIONS
(1) palpable or retiform and noninflammatory, such as hyperglobulinemic
purpura of Waldenström; (2) palpable or nonpalpable but inflammatory, such See Table 122 –1.
as Henoch-Schönlein purpura; and (3) nonpalpable and noninflammatory,
such as senile purpura. By accounting for palpability, presence of inflamma- DYSPROTEINEMIAS
tion, size, and shape, the differential diagnosis of a particular lesion can be Cryoglobulinemia
significantly reduced. Cryoglobulinemia refers to the presence in plasma of cold-insoluble
immunoglobulins, and is a secondary finding associated with several
5
disease states. Cryoglobulins are commonly present in low concentra-
DEFINITION AND DIAGNOSTIC tions, therefore approximately 90 percent of patients are asymptom-
atic or have minimal symptoms. Symptoms occur when the abnormal
6
APPROACH protein precipitates at the temperatures present in superficial venules
in the skin and acral parts of the body. Cryoglobulinemia syndromes
Purpura refers to visible hemorrhage into mucous membranes or skin, are divided into three main types based on the immunoglobulin
which corresponds to extravasation of red blood cells around small der- composition of the precipitate. Type I cryoglobulinemia results from
mal vessels and chronic hemosiderin deposition. Purpuric lesions, by the accumulation of monoclonal IgG, IgM, or IgA. It is most com-
1
definition, do not blanch completely upon compression, as opposed to monly seen in association with lymphoproliferative disorders, such
erythema. Blanching is commonly tested by compression of skin lesions as myeloma, Waldenström macroglobulinemia, or lymphoma. Type
with a glass slide, referred to as diascopy (Fig. 122–1). Certain condi- II, or mixed cryoglobulinemia involves formation of complexes com-
tions give rise to lesions that mimic purpura with incomplete blanch- posed of polyclonal IgG with monoclonal immunoglobulins, typically
ing upon diascopy, but are not purpura because no hemorrhage has IgM with anti-IgG specificity. Exposure to various exogenous anti-
occurred. Examples include disorders that impede on the red cell flow, gens appears to cause polyclonal immunoglobulin production, with
such as tortuous veins. 1 activity against bacteria, viruses, and fungi. Mixed cryoglobulinemia
Assessing lesion palpability is the first step in evaluating purpuric is commonly seen secondary to hepatitis C virus (HCV) infection,
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lesions (Fig. 122–2). The causes for palpability are varied and include HIV, collagen vascular disorders, and hematologic neoplasias. In
8,9
fibrin deposition, localized edema, significant cellular infiltration, and mixed cryoglobulinemia secondary to HCV infection, the presence
subcutaneous extravasation of red blood cells. of active cutaneous vasculitis correlates with increased levels of the
Inspecting the lesion for inflammatory changes is the next step in B-cell–attracting chemokine 1 (CXCL13). This process manifests
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evaluating purpuric lesions. The presence of pain, erythema, and palpa- with petechiae of the legs, palpable purpura, and necrotic skin ulcer-
tion for warmth and localized swelling are signs of inflammation and ations. First-line treatment includes use of interferon-α or other anti-
suggest a vasculitis or immune complex disorder. viral agents, often with adjunct glucocorticoids or plasmapheresis.
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Direct treatment of the HCV infection with ribavirin, interferon, or
other antiviral therapy, such as the protease inhibitors, ameliorates
this associated lymphoproliferative disorder. Deposition of immune
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Acronyms and Abbreviations: ANCA, antineutrophil cytoplasmic antibody; APS, complexes on vessel walls leads to tissue damage in the vasculature,
antiphospholipid syndrome; CSS, Churg-Strauss syndrome; DIC, disseminated intra- nerves, joints, and skin leading to the hallmark findings of mixed
vascular coagulation; HCV, hepatitis C virus; HHT, hereditary hemorrhagic telang- cryoglobulinemia: weakness, arthralgia, and purpura. This purpura
iectasia; HP, hypergammaglobulinemic purpura; HSP, Henoch-Schönlein purpura; often is palpable and is accompanied by areas of hemorrhagic necrosis
MELAS, mitochondrial encephalopathy, lactic acidosis, stroke-like; SLE, systemic (Fig. 122–3) and occasionally follicular pustular purpura. Other cuta-
lupus erythematosus; WG, Wegener granulomatosis. neous manifestations include lower-extremity ulcerations, urticaria,
Raynaud phenomena, and subungual purpura (Fig. 122–4). Type III

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