Perianal Thrombosis

Perianal thrombosis or anal thrombosis refers to the formation of very painful lumps in the area of ​​the anus outlet. It is uncomfortable but usually resolves on its own within a few weeks, leaving a fold of skin.

Perianal Thrombosis

What is perianal thrombosis?

Blood clots in the area of ​​the anus are referred to as perianal thrombosis, which occur in the form of nodules and can vary in size depending on the severity of the thrombosis. See electronicsencyclopedia for Slang ARM.

Light knots are only about the size of grapes, severe cases have been reported to have knots the size of plums or pigeon eggs. In some cases, multiple nodules form, or a nodule contains multiple thrombi. The nodes are red or appear bluish.

Painful water retention often occurs in addition to lump formation, which triggers additional feelings of tension, which further increases the pain caused by perianal thrombosis. Due to their similarity to hemorrhoids, perianal thrombosis is also known as “false hemorrhoids”.


Perianal thrombosis is caused by the formation of blood clots in the veins around the anus outlet. However, what causes these blood clots is a matter of controversy.

In the past, the doctrine was mostly held that prolonged sitting (especially on cold surfaces), high body pressure (e.g. when coughing, straining or lifting heavy weights, in women during childbirth or during the period) and the consumption of alcohol and spicy foods promote the development of perianal thrombosis.

Also, the existence of larger hemorrhoids could play a role in the formation of the blood clots. Recent studies suggest that intensive wet cleaning of the anal region and intensive physical activity can also entail a certain risk of perianal thrombosis developing.

Symptoms, Ailments & Signs

Perianal vein thrombosis is associated with severe pain and usually occurs without warning signs. Unlike hemorrhoids, these are not fine tissue protuberances filled with blood. Anal vein thrombosis has a strongly hardened structure. Their dimensions vary from knots the size of peas to plums.

The appearance is usually characterized by a dark red to bluish color. At first they are noticed by a subtle stinging in the anus area. After a short course, this sensation intensifies and the intensity of pain increases. Since the direct area of ​​the anus outlet is affected, the sphincter subsequently treats the already affected area. In addition to the actual pain, patients complain of permanent weeping itching.

Due to the blockade position, the anus does not close flush and secretion escapes from the rectum. Patients often confuse anal vein thrombosis with prolapsed hemorrhoids. These do not cause any significant pain in the first stages and remain mobile to a certain extent. In addition, they do not arise spontaneously in just a few minutes, but increase in size slowly and over time.

The hardened knot of a perianal vein thrombosis, on the other hand, is stuck and cannot be pushed back. In addition, it does not tend to bleed. Strong pressure occasionally leads to partial deflation without the knot receding. Those affected report sometimes considerable agony during bowel movements.

The passage of hard stool past the pressure-sensitive swelling is considered extremely uncomfortable. Walking and simply sitting on unpadded seats also cause patients great discomfort due to the constant friction of the knot.

Diagnosis & History

Perianal thrombosis develops within a very short time, although those affected often do not know the cause themselves. The knots are noticeable through severe pain and sometimes burning and itching, but are actually harmless and in many cases heal by themselves, which takes several days or even weeks.

If you are unsure about the diagnosis, you should consult your family doctor or a specialist doctor (proctologist or dermatologist). This is particularly indicated when the pain from the perianal thrombosis is so severe that those affected are severely restricted. Even after the healing of particularly pronounced thrombi, it can happen that an unsightly skin fold (a so-called skin tags) forms in the affected area, which can be surgically removed at the patient’s request.


In most cases, perianal thrombosis does not lead to any special complications or life-threatening symptoms. The lumps in the anus form relatively quickly on their own. However, scars or wrinkles can also remain on the skin itself. Patients suffer from very severe pain due to perianal thrombosis.

This pain is particularly unpleasant because it is usually no longer possible to sit normally. Defecation is also associated with severe pain. The constant pain often has a negative effect on the patient’s psyche, which can lead to depression or other psychological problems. Blood clots form in the anus itself, causing anal itching.

As a rule, no direct treatment is necessary for perianal thrombosis. The symptoms disappear relatively quickly and there are no further complications. The pain can be relieved with the help of painkillers. Laxatives can also soften the stool and thus reduce the pain. The perianal thrombosis does not affect the life expectancy of the person affected.

When should you go to the doctor?

Although perianal thrombosis usually heals on its own within a few weeks and leads to freedom from symptoms, a doctor’s visit should take place as soon as the first irregularities appear to be on the safe side. It is important to rule out serious illnesses in the person concerned and to create an optimal treatment plan to alleviate the symptoms. A doctor should be consulted if there is pain in the anus area. You should not take any pain medication until you have consulted your doctor, as complications and side effects can occur. In case of itching, bleeding or changes in the skin’s appearance, a doctor should be consulted.

A stinging sensation in the anus, bleeding and palpable lumps at the exit of the anus should be examined and treated. A doctor should be consulted in the event of inner restlessness, disturbances in locomotion and inconvenience when sitting. A decrease in well-being, swelling and ulcers must be treated by a doctor. If there are open wounds or the formation of pus, special care should be taken. If sterile wound care cannot be guaranteed, the help of a doctor should be accepted. In severe cases, the person affected is at risk of sepsis. Blood poisoning can be fatal without timely treatment. A feeling of pressure in the anus, changes in libido or sexual dysfunction should be discussed with a doctor.

Treatment & Therapy

In many cases it is sufficient to treat perianal thrombosis yourself, for example by applying creams and ointments that contain anti-inflammatory ingredients (anti- inflammatory drugs).

Taking pain-relieving medications by mouth, such as ibuprofen, which also has anti-inflammatory effects, can also relieve pain. For most sufferers, making sure that stools are as soft as possible during this time helps (for example, by using mild laxatives or eating a diet that includes plenty of fluids, perhaps dried fruit on an empty stomach and consuming flaxseed).

Sitz baths complete the therapy. For larger lumps or those that are extremely painful, the only option is often to see a specialist and have the thrombi cut open under local anesthesia, with the thrombi then being pushed out. This procedure can be performed by some general practitioners, but also by dermatologists, surgeons and proctologists. As a rule, healing then takes place quickly and without complications. If skin tags have formed, it is possible to have them surgically removed.

Outlook & Forecast

Perianal thrombosis usually heals without complications. After a few days to weeks, the healing process is complete with conservative therapy. Usually no damage remains and the tissue regresses completely. A spontaneous passage of the thrombus may occur, which is accompanied by bleeding. This leads to an immediate freedom from symptoms.

Sometimes perianal skin folds, so-called anal skin tags, form during healing. The skin tissue is severely overstretched by the thrombi and is then no longer able to completely regress. The skin tags do not cause any discomfort, but can be perceived as annoying by the patient. The skin folds can be removed as a whole under local anesthesia. There are hardly any risks with this procedure, but under certain circumstances it can lead to wound healing disorders.

With surgical treatment, immediate pain relief is achieved by eliminating the thrombosis. Rarely can scarring be seen or felt. Perianal thrombosis tends to recur. In conservatively treated patients, the rate is 15%. With surgical therapy, the probability decreases.


Since it is not exactly known what causes the formation of lumps as a result of perianal thrombosis, it is also difficult to consciously prevent this clinical picture. Until further research is carried out, it is therefore advisable to avoid prolonged sitting (on cold surfaces) or to interrupt sedentary activities again and again, to limit wet cleaning of the anal region or to change anal hygiene practices and to reduce the consumption of spicy foods or alcohol. A conscious relaxation when coughing or lifting or pressing is hardly possible.


Perinal thrombosis needs good follow-up care, whether it resolved spontaneously or was opened surgically. On the one hand, this is about the healing of a small wound that may have occurred in the anal canal. On the other hand, follow-up care is synonymous with prevention in order to prevent the development of a new perianal thrombosis.

Excessive hygiene in the anal area is strongly discouraged. Avoid harsh cleaning and very rough toilet paper. Normal washing with lukewarm water is sufficient, carefully patting the sensitive area dry.

Strong pressing promotes the recurrence of perianal thrombosis and also has an unfavorable effect on any wound healing that may be necessary. It is therefore important to regulate bowel movements so that they are not too hard. For this it is important to drink enough. Water and herbal teas are ideal. High-fiber foods are also recommended. Fruits and vegetables are just as helpful as whole grain products.

If this alone is not enough for targeted stool regulation, psyllium husks are a valuable helper. They are available in health food stores, among other things, are simply stirred into water and drunk after a short swelling phase. Drinking enough water is also important here.

Exercise is also important in the aftercare of perinatal thrombosis. It promotes digestion and the necessary intestinal movements and can thus avoid straining.

You can do that yourself

Perianal thrombosis is a symptom that the affected person can positively influence in everyday life through consistent behavior. In the acute phase, the main concern in this context is not to expose the anal vein thrombosis that is bulging or opened by the doctor to further irritation. This applies to long periods of sitting as well as to wearing tight pants. When it comes to hygiene after going to the toilet, the use of rough paper and damp toilet paper should be avoided. Strong rubbing is also better replaced by gently dabbing the affected areas on the edge of the anus.

In order to promote the rapid healing of a perianal thrombosis and to prevent further thrombosis in this area, behavioral changes in the patient that are closely related to nutrition are helpful. Anal vein thrombosis, like hemorrhoids, is often caused by pressure caused by straining when you have a bowel movement. It is therefore important in both the treatment and prevention of perinal thrombosis that constipation can be avoided.

Patients achieve this by eating a high-fiber diet and drinking a sufficient amount. If this does not work, the stool can be loosened using natural means such as psyllium husks or flaxseed, which are simply dissolved in water or stirred into yoghurt and then consumed. Food that causes flatulence is better to replace with alternatives in the acute phase.