White : Diseases of the Skin - Vascular Disorders

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Gary M. White & Neil H. Cox

Diseases of the Skin

15	Vascular Disorders

ARTERIAL DISEASE

Acute arterial insufficiency

Large-vessel obstruction

If a large embolus occludes a large vessel, the distal leg turns acutely white, as shown in Fig.15.43. This is a medical emergency, and the vascular surgeon should be consulted.

Diabetic foot

Diabetes mellitus can cause both a microangiopathy as well as atheroma of large vessels. Impaired arterial blood supply and even gangrene may result (Fig.15.44 and see Fig.12.9).

Arterial ulcers

Progressive impairment of arterial blood supply severely compromises the function of the skin. The skin of the lower extremities often exhibits pallor, cyanosis, loss of hair, and brittle or deformed nails. As the condition progresses, ulcers may develop.

The classic arterial ulcer does not occur on the medial ankle (where the venous ulcer is typical), but instead occurs on the toes, shins, or dorsa of the foot (Fig.15.45). Ischemic ulcers are often dry and punched out. Features of venous disease (brown pigmentation, stasis dermatitis, or lipodermatosclerosis) are absent. Elevation or compression bandaging will worsen symptoms of arterial disease. The differential diagnosis of leg ulcers is listed in Table 15.4.

Figure 15.43 Acute arterial insufficiency.

Figure 15.44 Diabetic foot with gangrene.

Unfortunately, a component of both arterial and venous disease may coexist in many patients, so the physical signs may be mixed.

Treatment of arterial ulcers may be difficult. Investigations by a vascular surgeon are typically required. Pressure should be avoided, and the nutritional and health status of the patient should be optimized. Any secondary infection should be addressed, and local wound care to promote healing should be provided. A specialist vascular nurse is often an asset in treating patients. Despite all these measures, healing often does not occur unless the arterial blood supply is improved with surgery. Excision and grafting may be necessary.

PRACTICE POINTS

•	Chronic leg ulcers are often best treated by a team of specialists, including the surgeon, wound care nurse, and dermatologists.
•	Compression is the most important aspect of treating venous ulcers but will worsen arterial ulcers.

Thrombophlebitis

Superficial thrombophlebitis may present to vascular surgeons, dermatologists, or generalists. Most cases are related to varicose veins, less commonly associated with deep venous thrombosis. Cases may be misdiagnosed as localized cellulitis or as solitary lesions of erythema nodosum due to the tenderness and erythema. However, lesions are often localized over areas of perforating veins at the ankle (Fig.15.46), or linear induration may be palpable following the course of a vein. Migratory thrombophlebitis is associated with internal neoplasia (especially of the pancreas; see Ch.12) but also occurs due to oral contraceptives, anticardiolipin antibodies, and thrombophilia (e.g. protein C or S deficiency), and in Behçet disease (see Ch.14).

Treatment is usually symptomatic (elevation, support stockings, and non-steroidal antiinflammatory agents), but anticoagulant drugs and fibrinolytic agents may be required.

Figure 15.45 Arterial ulcer. (a) A pretibial ulcer without associated pigmentation, stasis changes, or lipodermatosclerosis is typical. (b) Arterial ulcer after occlusion of the popliteal end of a femoral–popliteal graft.

Table 15.4 CAUSES OF LEG ULCERATION

Type of mechanism	Examples: common to moderately common	Examples: less common or rare
Venous disease	Varicose veins, deep vein thrombosis, other venous obstruction, ulcerated superficial thrombophlebitis	Congenital vascular malformations, Klippel–syndrome, ruptured varices
Arterial disease	Atherosclerosis, diabetes	Cholesterol emboli, obstruction (e.g. fat emboli), hypertensive ulcer, arteriovenous fistula
Vasculitis and neutrophilic dermatoses	Pyoderma gangrenosum, rheumatoid ulcers, small-vessel leukocytoclastic vasculitis (including Henoch–Schönlein purpura)	Other connective tissue disease (systemic erythematosus, systemic sclerosis) and livedoid vasculopathies
Other dermatoses and metabolic causes	Necrobiosis lipoidica, immunobullous diseases (e.g. pemphigoid)	Scleroderma, calciphylaxis
Genetic predisposition	(See hematologic causes, below)	Klinefelter syndrome, prolidase deficiency
Hematologic disorders and hyperviscosity	Sickle cell disease, thalassemia (common causes in some parts of the world)	Thrombophilias (Ch.14), cryoglobulinemia, hypergammaglobulinemias, spherocytosis, myeloproliferative disorders
Infections	Streptococcal cellulitis, leprosy, tropical ulcer, Buruli ulcer	Osteomyelitis, fungal infections, mycobacterial infections,leishmaniasis, necrotizing fasciitis
Peripheral neuropathy	Leprosy (common in some parts of the world),diabetes	Spina bifida, spinal injury, other spinal disorders
Trauma and extrinsic	Direct injury, pressure, burns, chemical injury (e.g. sclerotherapy, caustics such as cement), bites and stings (insects, snakes, stingray, etc.)	Intravenous drug use,dermatitis artefacta
Neoplasia	Basal cell carcinoma, squamous cell carcinoma	Merkel cell carcinoma,, Kaposi sarcoma, melanoma, malignant fibrous histiocytoma
Iatrogenic	After therapeutic radiation	Hydroxyurea

Figure 15.46 Thrombophlebitis. A linear ridge was palpable under this discoid area, demonstrating the importance of palpation. Presumably, a superficial thrombophlebitis extended into the perforator vessel at this site.

Cholesterol crystal embolization

This is an arterial wall disease etiologically, but usually presents in the skin as a livedo, or vasculitic or embolic disorder, and is discussed in Chapter 14.