Dermatology MCQ - Inflammatory Dermatoses - Stasis Dermatitis

An elderly patient presents with a several-month history of a pruritic rash confined to the lower legs. Physical examination reveals ill-defined, erythematous, scaly plaques with moderate edema and a notable brownish-orange discoloration of the skin surrounding the plaques. There is evidence of pitting edema at the ankles and bilateral varicose veins. What is the most likely diagnosis?

A. Nummular Dermatitis
B. Asteatotic Eczema
C. Stasis Dermatitis
D. Allergic Contact Dermatitis
E. Psoriasis

Correct Answer: C. Stasis Dermatitis

Explanation:

• The presentation is classic for stasis dermatitis. The key diagnostic clues are the location (lower legs), the presence of signs of chronic venous insufficiency (varicose veins, pitting edema), and particularly the brownish-orange discoloration, which represents hemosiderin deposition from the breakdown of extravasated red blood cells. This is a hallmark finding that strongly points toward a venous etiology.

• Why the other options are incorrect:

  • A. Nummular Dermatitis: While common on the legs, this presents as well-circumscribed, coin-shaped plaques. It is not typically associated with the signs of venous hypertension like significant edema, varicose veins, or hemosiderin deposition.

  • B. Asteatotic Eczema: This presents with dry skin and a characteristic crazed or cracked pattern (eczema craquelé). It lacks the signs of venous stasis such as prominent edema and the characteristic brownish discoloration.

  • D. Allergic Contact Dermatitis: This would present with a more acute, intensely inflamed, and often vesicular eruption. Its distribution would correspond to contact with an allergen (e.g., from topical medications, footwear). It is not associated with the chronic signs of venous disease.

  • E. Psoriasis: Plaque psoriasis on the legs presents as well-demarcated, thick, silvery-scaly plaques. While it can occur on the legs, it is not associated with edema, varicose veins, or hemosiderin deposition. Psoriasis can be exacerbated by local trauma (Koebner phenomenon), but the clinical findings here are specific for venous pathology.

Key Points for Exams

• Pathophysiology: Stasis dermatitis results from chronic venous hypertension leading to increased capillary pressure, leakage of fibrinogen and red blood cells, and eventual inflammation.

• Clinical Sequelae: It is a precursor to more severe complications. Persistent inflammation and poor healing can lead to venous ulcers, which most commonly occur on the medial malleolus.

• Prognosis: The condition is chronic and progressive. The goal of management is to control symptoms, reduce edema, and prevent complications like ulceration and secondary cellulitis.

• Management:

  1. Compression Therapy: The cornerstone of treatment. Graduated compression stockings or bandages are essential to counteract venous hypertension and reduce edema.

  2. Leg Elevation: Elevating the legs above the level of the heart whenever possible assists venous return.

  3. Topical Therapy: Low- to mid-potency topical corticosteroids are used for short courses to reduce inflammation and pruritus. Emollients are crucial to maintain the skin barrier.

  4. Treatment of Complications: Any signs of secondary infection (impetiginization) or cellulitis require appropriate systemic antibiotics. Venous ulcers require specialized wound care in addition to compression.

  5. Important Caveat: Compression is contraindicated in the presence of significant arterial disease. An Ankle-Brachial Index (ABI) should be checked if peripheral arterial disease is suspected.