They are dilated terminal ramifications of the superior and middle rectal veins, which drain tissues above the pectinate line. Haemorrhoids of this type are typically produced by intense contractions during the passage of hard faeces. External haemorrhoids are dilated terminal ramifications of the inferior rectal vein, which drains tissues below the pectinate line. Haemorrhoids of this type may extrude through the anal sphincter during defecation, but typically retract spontaneously or can be pushed back in manually. Alternatively, they may remain external.
Mixed haemorrhoids are concurrent internal and external haemorrhoids.
After two or three days, the clot may be reabsorbed so that the pain is reduced, or it may ulcerate and worsen. Symptoms Pruritus in the perianal region is characteristically the first symptom of haemorrhoids, and typically the most distressing for the patient. It tends to aggravate inflammation. As a result of scratching by the patient, or simply because of friction between clothing and the skin, the affected area becomes increasingly irritated and it is more difficult to clean. Pain is not always present, and when present is generally a 'dull' pain.