Piles -

Haemorrhoids, commonly known as piles, are swollen blood vessels in or around the anus and rectum. The haemorrhoidal veins are located in the lowest part of the rectum and the anus. Sometimes they swell so that the vein walls become stretched, thin, and irritated by passing bowel movements. Haemorrhoids are classified into two general categories - internal and external.

What Causes Haemorrhoids?

Anyone at any age can be affected by piles. 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. Researchers are not certain what causes haemorrhoids. "Weak" veins - leading to haemorrhoids and other varicose veins - may be inherited.
It's likely that extreme abdominal pressure causes the veins to swell and become susceptible to irritation. The pressure can be caused by obesity, pregnancy, standing or sitting for long periods, straining on the toilet, coughing, sneezing, vomiting, and holding your breath while straining to do physical labour.
Diet has a pivotal role in causing - and preventing - haemorrhoids. People who consistently eat a high-fibre diet are less likely to get haemorrhoids, but those who prefer a diet high in processed foods are at greater risk of haemorrhoids. A low-fibre diet or inadequate fluid intake can cause constipation, which can contribute to haemorrhoids in two ways: it promotes straining on the toilet and it also aggravates the haemorrhoids by producing hard stools that further irritate the swollen veins.

Symptoms -

In most cases, the symptoms of piles are not serious. They normally resolve on their own after a few days.
An individual with piles may experience the following symptoms:
A hard, possibly painful lump may be felt around the anus.
It may contain coagulated blood.
Piles that contain blood are called thrombosed external hemorrhoids.
After passing a stool, a person with piles may experience the feeling that the bowels are still full.
Bright red blood is visible after a bowel movement.
The area around the anus is itchy, red, and sore.
Pain occurs during the passing of a stool.

Piles can escalate into a more severe condition. This can include:
excessive anal bleeding, also possibly leading to anemia
infection
fecal incontinence, or an inability to control bowel movements
anal fistula, in which a new channel is created between the surface of the skin near the anus and the inside of the anus
a strangulated hemorrhoid, in which the blood supply to the hemorrhoid is cut off, causing complications including infection or a blood clot

Piles is classified into four grades:

Grade I: There are small inflammations, usually inside the lining of the anus. They are not visible.
Grade II: Grade II piles are larger than grade I piles, but also remain inside the anus. They may get pushed out during the passing of stool, but they will return unaided.
Grade III: These are also known as prolapsed hemorrhoids, and appear outside the anus. The individual may feel them hanging from the rectum, but they can be easily re-inserted.
Grade IV: These cannot be pushed back in and need treatment. They are large and remain outside of the anus.
External piles form small lumps on the outside edge of the anus. They are very itchy and can become painful if a blood clot develops, as the blood clot can block the flow of blood. Thrombosed external piles, or hemorrhoids that have clotted, require immediate medical treatment.