While no exact cause of hemorrhoids is known, the American Society of Colon & Rectal Surgeons says pressure on the anal veins because of a human's upright posture can cause them. Other factors that contribute to the development of hemorrhoids include aging, pregnancy, constipation, spending a lot of time on the toilet and straining when trying to defecate.
When pressure is put on the anal area, tissues that surround the anal vessels are stretched, explains the ASCRS. As they stretch, they are weakened. Weakened vessels that protrude through the anal tissues are hemorrhoids.
Lifestyle changes, such as eating foods high in fiber, drinking fluids and going to defecate as soon as the urge occurs, can help minor hemorrhoids heal and may prevent new hemorrhoids, notes Mayo Clinic. Additionally, people who have hemorrhoids or who are at risk of developing them are advised to avoid sitting for prolonged periods of time.
When hemorroids have become more severe, medical interventions are sometimes necessary, notes Mayo Clinic. This can include topical treatments, non-invasive procedures or surgery.
Anyone who has rectal bleeding or who has hemorrhoids that do not resolve with home treatment should seek medical care, according to PubMed Health. Severe bleeding or bleeding accompanied by dizziness, lightheadedness or faintness requires urgent medical care.
According to Harvard Medical School, hemorrhoids are rarely, if ever, dangerous, but they can be uncomfortable and painful if left untreated. Hemorrhoids are divided into two types depending on where they form. Internal hemorrhoids develop among deep veins and rarely cause discomfort, but they can cause rectal bleeding with bowel movements. External hemorrhoids can be very painful because their surfaces are exposed to the alimentary canal and are subject to irritation by passing feces. They frequently become inflamed and are prone to clotting.