Until they thrombose or bleed you may not know you have them. External hemorrhoids develop under the skin just outside the opening of the anus. They are tender to the touch and are round and purple in colour. While there is no conclusive evidence as to the specific cause of hemorrhoids, there is a long list of contributing factors. These include constipation, straining during a bowel movement, pregnancy, lifting heavy objects, prolonged sitting or standing, being overweight, and faulty diet.
Downward pressure can cause the small veins around the anus and rectum to stretch.
As the veins lose their elasticity and retain excess blood, they become more vulnerable to injury, possibly triggering bleeding, which is often the first indication of hemorrhoids. Some people can have a single episode of hemorrhoids, and others are plagued by them all their lives. People who sit or stand for extended periods on their jobs have a higher risk of developing hemorrhoids. Hemorrhoids are most common in the 25-54 age group. While about half of hemorrhoid sufferers have a family history of the condition, diet may be responsible.