Haemorrhoids, also known as piles, are enlarged and swollen blood vessels in or around the lower rectum and back passage (anus). When the pressure inside these blood vessels is increased, they swell and form small lumps. Increased pressure is often caused by straining when trying to pass a stool.
Haemorrhoids often begin with an itchy feeling around the anus, but can become painful and lead to bleeding. The condition is not very serious and can be successfully treated.
Anyone at any age can be affected by haemorrhoids. They are very common, with about 50% of people experiencing them at some time in their life. However, they are usually more common in elderly people and during pregnancy.
Types of haemorrhoids
Haemorrhoids vary in size and can occur internally (inside) or externally (outside) the anus. Internal haemorrhoids develop in the back passage, 2-4cm above the rim (opening) of the anus. External haemorrhoids (perianal haematoma) are less common, and develop on the outside edge of the anus.
Internal haemorrhoids are classified using a grading system from one to four.
- Grade one haemorrhoids are small swellings often inside the lining of your anus. They cannot be seen and are very common. In some cases they will enlarge to grade two.
- Grade two haemorrhoids are larger in size but are still within your anus. Sometimes they become pushed out when you pass a stool, but will return inside immediately after.
- Grade three haemorrhoids appear outside your anus; you may be able to feel one or more small lumps hanging out. They are also referred to as prolapsed haemorrhoids. You'll usually be able to push them back inside using your finger.
- Grade four haemorrhoids can become quite large and remain outside your anus permanently. They cannot be pushed back inside and will need to be treated.
External haemorrhoids, also known as perianal haematoma, are small lumps that develop on the outside edge of the anus. They can become increasingly itchy. If a blood clot forms inside them (thrombosed external haemorrhoid) it can cause a lot of pain, requiring immediate treatment. This type of haemorrhoid is less common.