What bad diseases are associated with varicose veins?

Varicose vein : Venous stasis ulcers, venous stasis dermatitis, pitting edema to name a few of the long term sequelae. Skin disoloration, and ulcers being the worst.

In addition ... : To the things that dr. Mountcastle mentioned, having varicose veins also increases you risk of getting phlebitis and thrombophlebitis. Thrombophlebitis is associated with a higher risk of developing a deep venous thrombosis which can increase your risk of having a blood clot in your lungs.