Cause of Varicose Veins
Genetic dysfunction of the valve or wall of the vein is the commonest cause. Rarely malformations or congenital absence of the valves are responsible for the development of the disease. Persistently increased intravenous pressure damages the venous walls and results in stretching and loss of elasticity. This will produce a backflow (reversal of blood flow) due to the gravitational force. Occasionally,  any block to the normal flow of blood through the deep vein of the leg either due to intrinsic or extrinsic  factors may produce varicose vein.

The predisposing factors
1) Age : As age advances the frequency of the disease may increase, maximum incidence observed around 50 years of age
2) Sex : There is a female predominance, obviously due to pregnancy
3) Racial factors
4) Hereditary / Genetic Factors : The commonest
5) Hormonal :  Due to the Effect of female hormone
6) Pregnancy : Due to the Pressure effect of  gravid uterus on the major veins of  the lower abdomen (pelvic veins)
7) Secondary to Diseases: Fibroid Uterus, Lower abdominal tumors
8) Secondary to Deep Vein Thrombosis
9) Chronic Constipation
10) Occupational: Standing for long time was considered as a common predisposing factor but recent studies shows, sitting is worse than standing

Pain: Dull aching pain in the lower leg is the commonest early symptom
Swelling of the feet: Oedema of the feet especially on standing for long time or by evening  is  the commonest sign
Bleeding: Seen only in  very limited  number of patients. It has no relation to age, stage of the disease, or the size of the vein or the stage of the disease
Itching: Experienced only below the knee and the maximum at the lowermost part of the leg
Discoloration: Blackish discoloration (pigmentation) around the ankle joints and the  lower leg.The upper one third of the leg is spared.
Eczematous Change: Around the ankle, foot or lower leg
Lipodermatosclerosis: Leathery skin with pigmentational changes
Atrophie Blanche: It is a localised, circular area of atrophic skin surrounded by very fine veins. There can have pigmentation around. This may be sometimes mistaken for healed ulceration
Ulcer Formation: Initially small ulcers develop and heal spontaneously over a period of time
Giant Ulcers:  Later in the course of the disease, the ulcers refuse to heal and proceed to progressive skin erosion resulting in very  large non healing ulcers
Malignant changes: The chronic ulcer may turn malignant