External hemorrhoids usually have no special symptoms, but can be swollen and painful when thrombosis and inflammation occur. The painful swelling during the attack is clinically divided into four types: a. Connective tissue external hemorrhoids: connective tissue external hemorrhoids, also known as dermal hemorrhoids or dermal hemorrhoids. The hemorrhoid is basically a connective tissue change, no obvious varicose veins, few blood vessels, wide and long at the bottom, yellowish brown or brownish black, prominent and easy to see, varying in size and shape, sometimes only one, in the back of the anus or front and center, sometimes several around the anus. The varicose external hemorrhoids: varicose external hemorrhoids are varicose veins below the dentate line, forming round, oval or prismatic soft masses at the anal edge. If there is edema, the shape becomes larger. It increases in size during defecation, and the symptoms can be reduced to varying degrees after returning to normal position. Inflammatory external hemorrhoids: Inflammatory external hemorrhoids are caused by inflammation on the basis of connective tissue external hemorrhoids, varicose veins external hemorrhoids, also seen in the acute inflammatory phase of thrombosed external hemorrhoids. It is often caused by skin injury and infection at the anal verge. The skin of the anal verge protrudes from the wall like a blister. The swelling and pain are obvious. Four, thrombosed external hemorrhoids: often due to excessive consumption of spicy and stimulating food, stool prostrate struggle, perianal subcutaneous vein rupture, blood pooling subcutaneous and become. It is characterized by sudden onset, local swelling and severe pain.