Yes, varicose veins can lead to the formation of blood clots, particularly in deeper veins (a condition known as deep vein thrombosis, or DVT). This is more likely if there is an underlying blood flow issue or if varicose veins become inflamed (a condition called phlebothrombosis). Clots can be dangerous and require medical treatment. If you experience swelling, redness, and warmth in the affected leg, along with pain, seek medical attention immediately