A 58-year-old man, who has not seen a physician in 10 years, comes to the office to establish care. He reports dry itchy skin over his legs and increased leg discomfort at the end of the day. He also has had steady weight gain of about 9 kg (20 lb) over the last 5 years. The patient has no history of chronic medical conditions and takes no medications. He has smoked a pack of cigarettes a day for 30 years but is trying to quit because his brother was recently diagnosed with lung cancer. Blood pressure is 150/84 mm Hg, pulse is 80/min, respirations are 16/min, and pulse oximetry is 98% on room air. BMI is 34 kg/m². Neck examination shows no jugular venous distention and a normal thyroid gland. Cardiopulmonary examination reveals normal heart sounds and mild end-expiratory wheezing. The lower extremities are warm to the touch below the knees bilaterally and have weakly palpable peripheral pulses. Intertrigo is present in inguinal creases. Skin findings are shown in the image below. Which of the following is most likely to identify the cause of this patient's skin condition?

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11ec25c8_d23e_7c6c_bc81_5d6880cc44ca_MD0003_00 This patient has chronic stasis dermatitis due to venous insufficiency. Venous stasis is common in patients who are older, obese, or have a history of venous thrombosis. Increased intraluminal pressure or loss of vessel wall tensile strength can lead to venous dilation and failure of the venous valves. The resulting backflow of blood exacerbates the venous hypertension, leading to further valvular incompetence and venous congestion. Elevated venous pressure and increased vascular permeability lead to extravasation of fluid, plasma proteins, and red blood cells. Clinical manifestations include scaling, weeping, superficial erosions, and pitting edema. Itching and achy pain are common but usually mild. Acute inflammation can manifest as erythema and warmth resembling cellulitis (although unlike cellulitis, it is typically bilateral and symmetric). Chronic findings include red/brown discoloration (due to deposition of hemosiderin), woody induration, and fibrosis. Microvascular disease, platelet aggregation, and increased expression of proteolytic enzymes can cause chronic irregular ulcers, most commonly at the medial malleolus. erythema ulcers The diagnosis of stasis dermatitis is usually obvious based on clinical findings. Duplex ultrasonography is not routinely performed but can confirm venous hypertension and reflux and rule out venous thrombosis in patients with acute unilateral symptoms. Management includes compression stockings, leg elevation, exercise, and avoidance of prolonged standing. (Choice A) Ankle brachial index is used to evaluate lower extremity arterial insufficiency; common indications include intermittent claudication, dermal atrophy, and absent distal pulses. This patient's skin discoloration and palpable pulses are more consistent with venous insufficiency. (Choice B) Necrobiosis lipoidica diabeticorum (NLD) is a skin condition frequently seen in patients with diabetes. Because the skin lesions may precede the onset of diabetes, patients should be screened with a hemoglobin A1c or fasting blood glucose. Although NLD typically occurs in the pretibial areas, it presents as multifocal lesions with a brownish hue, dilated blood vessels, and central epidermal atrophy. multifocal lesions (Choice C) Inguinal lymph node biopsy is indicated for lower extremity malignancy, especially melanoma. Melanoma typically presents as a focal pigmented lesion with an asymmetric, irregular border. This patient's skin changes involve most of the lower leg, which is more consistent with stasis dermatitis. (Choice D) Thyroid dermopathy is typically seen in patients with Graves disease and presents as induration and thickening of the skin over the shins (pretibial myxedema). It is almost always associated with other signs of Graves disease (eg, goiter, ophthalmopathy). (Choice E) Allergen patch testing can be considered for chronic lower extremity dermatitis that worsens despite appropriate treatment or involves specific areas of allergen exposure (eg, under footwear). Allergic contact dermatitis typically involves limited, well-demarcated areas and is characterized by significant itching and lichenification. (Choice F) Skin biopsy is rarely needed for diagnosis of stasis dermatitis and should be avoided because the involved skin heals poorly. Indications for biopsy include atypical symptoms, solitary or unilateral disease, and suspicion for malignancy. Educational objective: Stasis dermatitis is characterized by scaling, weeping, superficial erosions, and pitting edema. Chronic findings include red/brown discoloration, woody induration, fibrosis, and chronic ulcers. The diagnosis is primarily based on clinical findings, although duplex ultrasonography can confirm venous hypertension and reflux. References: Stasis dermatitis: pathophysiology, evaluation, and management. (http://www.ncbi.nlm.nih.gov/pubmed/28063094)

A 58-Year-Old Man, Who Has Not Seen a Physician in 10