Chronic Venous Insufficiency (CVI): This condition is characterized by the veins having problems returning blood from the legs back to the heart due to valve issues. Symptoms include aching legs, visible veins (varicose veins), and cold legs due to poor circulation, which can lead to numbness.

Peripheral Artery Disease (PAD): This condition involves the narrowing of the peripheral arteries, typically in the legs, which can cause pain, numbness, and coldness in the legs. While it primarily affects older adults, especially smokers, the symptoms overlap significantly with those described.
Deep Vein Thrombosis (DVT): Although DVT typically presents with acute onset of leg swelling, pain, and warmth, chronic or recurrent DVT could lead to symptoms of chronic venous insufficiency, including visible veins and numbness due to chronic inflammation and damage to the venous system.
Diabetic Neuropathy: For patients with diabetes, neuropathy can cause numbness in the legs. While it doesn't directly cause visible veins, the combination of diabetes with other vascular issues could explain the full spectrum of symptoms.

Acute Limb Ischemia: A sudden decrease in limb perfusion that threatens limb viability, requiring immediate medical attention. Symptoms can include the six Ps: pain, pallor, pulselessness, poikilothermia, paresthesias, and paralysis. Missing this diagnosis could result in loss of the limb or even death.
Compartment Syndrome: A condition resulting from increased pressure within a muscle compartment, which can lead to muscle and nerve damage. Symptoms include severe pain, especially on palpation, and paresthesias. It's a medical emergency that requires prompt intervention.

Ehlers-Danlos Syndrome: A group of disorders that affect connective tissues supporting the skin, bones, blood vessels, and many other organs and tissues. Some types can lead to easy bruising, poor wound healing, and potentially visible veins due to fragile blood vessels, though it's less directly linked to the primary symptoms.
Buerger's Disease (Thromboangiitis Obliterans): A rare disease of the arteries and veins in the arms and legs, leading to blockages that can result in pain, numbness, and coldness. It's strongly associated with smoking and typically affects younger individuals.