Haemorrhoids: what they are, symptoms and causes - THDLAB - COM

  • What are haemorrhoids
  • Haemorrhoidal disease
  • Haemorrhoids: grades
  • Haemorrhoids: symptoms
  • Haemorrhoids: causes and risk factors

What are haemorrhoids

Haemorrhoids are normal anatomical structures which we all have, located near the anal canal.

The haemorrhoidal plexus is the set of cushions formed by the blood vessels of the haemorrhoids. Haemorrhoidal cushions are made up of a dense network of blood vessels equipped with valves which, by opening and closing, determine their dilation or distension.

Haemorrhoids help with continence control, especially of liquid and gas faeces, as they expand due to the blood flow, contributing to closing the anus.

Haemorrhoids can be internal or external:

Internal haemorrhoids

Internal haemorrhoids are the cushions placed above the "dentate line", the area which marks the upper margin of the anal canal. The dentate line is also called the "pain line" because below this area we perceive painful stimuli.

External haemorrhoids

External haemorrhoids are the haemorrhoidal cushions placed under the "dentate line". External haemorrhoids are covered with anoderm, a very sensitive layer of skin which also covers the outer wall of the anus.


Haemorrhoidal disease

Haemorrhoidal disease is one of the most common proctologic diseases in western countries.

The main symptoms of haemorrhoids are:

  • bleeding: the haemorrhoids are more sensitive and bleed.
  • haemorrhoidal prolapse: the haemorrhoids increase in volume and prolapse.
  • haemorrhoidal thrombosis: a blood clot forms inside the haemorrhoidal cushions; this takes on a bluish-red colour.

Based on the severity of the disease, we can distinguish between I, II, III and IV grade haemorrhoids.


Haemorrhoids: grades

Haemorrhoids are classified based on symptoms and this is important for the choice of the most suitable treatment.

  • GRADE I: haemorrhoids visible at an anoscopy which can escape under stress, even though they are not prolapsed.
  • GRADE II: visible prolapse on the anal margin under stress which spontaneously reduces at the end of this.
  • GRADE III: persistent prolapse of the mucosa outside the anal canal which can be reduced manually.
  • GRADE IV: permanent prolapse of the mucosa outside the anal canal which cannot be reduced manually.

Haemorrhoids: symptoms

The most common symptoms of haemorrhoids are bleeding, pain, anal itching and prolapse.


In the presence of hemorrhoidal disease, the haemorrhoidal cushions are more sensitive to trauma and bleed more easily. Bleeding haemorrhoids are one of the main symptoms of the disease and one of the aspects which most worries sufferers.

In less severe cases, the loss of bright red blood on toilet paper or faeces is mild and infrequent. On the contrary, in advanced cases, haemorrhoidal bleeding can be constant. Blood loss occurs mainly in the presence of internal haemorrhoids.


Another frequent symptom is pain, often present for both internal haemorrhoids and external haemorrhoids. Normally, internal haemorrhoids are associated with pain only when their volume increases so much as to cause a significant swelling of the anus. In these cases, the pain, or its intensification, is felt when defecating.

Anal itching

Where pain is a more frequent symptom of external haemorrhoids, anal itching is often linked to internal haemorrhoids. Internal haemorrhoids tend to secrete mucus which causes irritation and itching in the anal area.


The swelling of one or more haemorrhoidal cushions, with the concomitant sagging of the supporting tissue, causes the haemorrhoids to escape from the anal canal during defecation (hemorrhoidal prolapse). The prolapse can reduce spontaneously, require manual reduction or be non-reducible depending on the severity of the disease.

The choice of the most suitable treatment largely depends on the severity of the prolapse.

The evaluation of the prolapse through a rectal examination is therefore fundamental.


Haemorrhoids: causes and risk factors

Vascular theory is one of the most reliable explanations of the causes of haemorrhoids.

Vascular theory

According to the vascular theory, haemorrhoids are varicosities caused by an altered blood flow. The increase in arterial flow and the decrease in the venous flow causes a swelling of the haemorrhoids. In severe cases, congestion of haemorrhoids can lead to haemorrhoidal prolapse.

Other factors

There are also a number of factors that can contribute to the onset of the haemorrhoidal disease, including:

  • family history
  • environmental factors (e.g. low-fibre diet, sedentary lifestyle)
  • pregnancy
  • obesity
  • constipation