On their own, varicose veins may just appear like an annoying problem to have, let alone the unsightliness of the veins bulging out.
They are not dangerous short term, when they are just starting out. The challenge is sometimes by the time they are seen externally, they have already been present internally for years but have not showed themselves on the skin. Therefore it depends what stage they are when first noticed.
The process of development of varicose veins starts much earlier internally within the veins before it is ever seen outside. This then progresses and worsens over time.
The dangers associated with mid level to advanced varicose veins is the potential development of a superficial venous thrombosis or deep vein thrombosis (DVT). Essentially clots within the veins. If you have previously had a DVT and have varicose veins then your risk increases dramatically. Blood clots in the leg can travel up to the lungs, heart and brain which makes them a dangerous association.
Other than the dangers of a clot, the deterioration of the skin, bleeding from the veins as well as wound formation are not imminent threats but can become a major health issue as it worsens that sometimes is not irreversible.