Anal thrombosis

The formation of a blood clot in the superficial veins of the anus gives rise to a perianal thrombus manifesting as one or more bluish-red lumps at the anal margin.
The thrombus causes an acute sensation of pain in the anal skin nerves. The reasons are not known. Anal thrombosis can also be accompanied by itching, burning, and bleeding. Unlike anal abscesses, anal thrombosis usually starts with severe symptoms, which abate substantially after two to three days.

Anal thrombi are often confused with hemorrhoidal disease and therefore mistakenly referred to as external hemorrhoids. They can occur acutely after the person has sat on a cold surface or result from physical exertion. Moreover, anal thrombosis frequently occurs after long-distance flights. Women may be affected during pregnancy and at delivery. Sometimes the development of anal thrombosis is triggered by diarrhea, while in other cases it may be related to the presence of large piles.

Treatment concepts in anal thrombosis may differ from those in hemorrhoidal disease. It is therefore important to establish the correct diagnosis soon after the symptoms occur. We thus recommend that you should see your doctor.