A 50-year-old male patient presented to the dermatology OPD with characteristic skin lesions on the right shin. The skin lesion is a single indurated yellowish-brown plaque with atrophic centre. Some ectatic blood vessels are visible through the thinned skin. A biopsy sample was taken and HPE examination was done. Which of the following is the next best investigation to be done in the patient: –

**Core Concept**
The patient's presentation is suggestive of a stasis dermatitis or more likely, a stasis ulcer secondary to chronic venous insufficiency. This condition is characterized by impaired venous return, leading to increased pressure and subsequent skin changes.

**Why the Correct Answer is Right**
The next best investigation would be Doppler ultrasonography to evaluate the venous outflow. This non-invasive test assesses the velocity and direction of blood flow in the deep and superficial veins, providing valuable information on the presence and severity of venous insufficiency. The patient's symptoms and physical examination findings, such as ectatic blood vessels and atrophic skin, are consistent with chronic venous insufficiency.

**Why Each Wrong Option is Incorrect**
**Option A:** Venous angiography may be used to visualize the venous system, but it is more invasive and typically reserved for situations where Doppler ultrasonography is inconclusive or not feasible.

**Option B:** Arterial Doppler ultrasonography is used to evaluate arterial flow, not venous outflow, making it an inappropriate choice for this patient.

**Option C:** MRI venography may be useful in certain cases, but it is more expensive and not typically the first-line investigation for chronic venous insufficiency.

**Option D:** A complete blood count (CBC) may be ordered to evaluate for signs of infection or inflammation, but it does not directly assess the underlying cause of the patient's skin lesions.

**Clinical Pearl / High-Yield Fact**
Chronic venous insufficiency is a common condition that can lead to significant morbidity if left untreated. The CEAP classification system (C - clinical, E - etiology, A - anatomy, P - pathophysiology) is a useful tool for staging and managing patients with chronic venous insufficiency.

**Correct Answer:** C.

✓ Correct Answer: A. Blood sugar levels