What Are Thrombosed Haemorrhoids: A Complete Guide Piles, commonly known as swollen rectal veins, are dilated veins in the anal area. If a clot develops in a haemorrhoid, it causes a thrombosed haemorrhoid—a painful condition affecting daily life. Below, explore the symptoms, triggers, and treatment options for this painful condition. https://www.zupyak.com/p/4593967/t/what-are-thrombosed-haemorrhoids-or-piles