What is the likely diagnosis and treatment for abnormal microvascular changes at the surface of the skin, typically found below the knee, in a non-inflammatory context, in a Caucasian patient?

Corona Phlebectasia (Ankle Flare)

The most likely diagnosis is corona phlebectasia (ankle flare), a benign non-inflammatory microvascular change representing dilated intradermal venules at the medial ankle, typically found in Caucasian patients and strongly associated with underlying chronic venous insufficiency. 1

Clinical Characteristics

Corona phlebectasia presents as clusters of small bluish-red telangiectatic vessels arranged in a fan-like or sunburst pattern around the medial malleolus. 2 These represent dilated intradermal venules measuring less than 1mm in diameter that are visible through the skin surface. 3, 4

• The lesions are asymptomatic and non-inflammatory, distinguishing them from active venous dermatitis or cellulitis. 5
• They appear as red-purple focal lesions representing prominent small vessels (venules, capillaries) visible in the skin. 4
• The distribution is characteristically bilateral and symmetric, favoring the medial lower legs and gaiter area below the knee. 5

Pathophysiology and Clinical Significance

Corona phlebectasia develops secondary to chronic venous hypertension, representing an early marker of venous insufficiency before more advanced skin changes develop. 5 The condition results from increased capillary permeability and venous pressure transmitted to the superficial venous plexus. 2

• These microvascular changes serve as a cutaneous marker for underlying chronic venous disease and warrant evaluation for venous reflux. 5, 4
• The presence of corona phlebectasia corresponds to CEAP classification C1 (telangiectasia or reticular veins) when isolated, but often indicates progression toward more severe venous disease. 2, 1
• Patients with corona phlebectasia have significantly higher rates of saphenofemoral junction reflux and may progress to lipodermatosclerosis if venous insufficiency remains untreated. 5

Diagnostic Approach

Immediate evaluation with duplex ultrasound is indicated to assess for underlying venous reflux, particularly at the saphenofemoral and saphenopopliteal junctions. 1, 5 The ultrasound should document:

• Direction of blood flow and assessment for venous reflux (pathologic if >500 milliseconds). 1
• Vein diameter measurements at key junctions. 1
• Condition of the deep venous system to exclude post-thrombotic syndrome. 2, 1
• Extent of refluxing superficial venous pathways. 1

Associated findings that suggest progression to more advanced venous disease include varicose veins, edema, skin induration, hyperpigmentation, and dermatitis. 5 The absence of acute inflammatory signs (warmth, tenderness, rapid progression) helps exclude cellulitis or other acute processes. 5

Treatment Algorithm

Conservative Management (First-Line)

For isolated corona phlebectasia without symptoms or advanced venous disease, conservative management with compression therapy is appropriate. 1 This includes:

• Prescription-grade gradient compression stockings (20-30 mmHg minimum). 1
• Leg elevation and exercise to improve venous return. 1
• Weight loss if obesity is present. 2

Interventional Treatment Considerations

If duplex ultrasound reveals significant venous reflux (>500ms) with saphenofemoral or saphenopopliteal junction incompetence, endovenous thermal ablation should be considered to prevent progression to more severe venous disease. 1 The treatment sequence follows:

• Endovenous thermal ablation (radiofrequency or laser) for main saphenous trunks with documented reflux and diameter ≥4.5mm. 1
• Foam sclerotherapy or laser therapy for residual telangiectatic vessels after treating underlying venous reflux. 1, 3

Treating corona phlebectasia alone without addressing underlying saphenofemoral junction reflux results in recurrence rates of 20-28% at 5 years. 1 The flashlamp pumped pulsed dye laser at 585nm can lighten smaller red telangiectatic vessels up to 0.4mm diameter, though hyperpigmentation frequently develops after treatment. 3

Critical Clinical Pitfall

The most common error is treating corona phlebectasia cosmetically without evaluating for underlying venous insufficiency. 1, 5 Hyperpigmentation alone is insufficient for diagnosis—always palpate for induration and assess for other signs of venous disease including edema, varicosities, and skin changes. 5 Failure to identify and treat underlying venous reflux leads to progression toward lipodermatosclerosis, venous ulceration, and significantly impaired quality of life. 5