Internal hemorrhoids involve the swelling of vascular cushions located within the anal canal. These swollen vein-like structures develop inside the rectum, originating above the dentate line. Understanding their location is fundamental to grasping the sensations they produce, as the nerve supply in this region dictates the type of discomfort experienced. This internal position means that the symptoms are often distinctly different from those associated with hemorrhoids located closer to the anal opening.
The Typical Sensation of Uncomplicated Internal Hemorrhoids
When internal hemorrhoids remain contained within the rectum, they typically produce no pain. This is explained by their location, which is innervated by visceral nerves. These nerves primarily detect stretching and pressure, not sharp pain, making the hemorrhoids largely asymptomatic in their early stages. The most frequently reported sign is painless bleeding, appearing as bright red blood on the toilet paper, coating the stool, or dripping into the toilet bowl. This occurs when the fragile surface tissue covering the enlarged vessels is scraped during a bowel movement.
Instead of pain, the sensation is usually one of fullness or a heavy feeling deep within the anal canal. Some individuals may experience tenesmus, the persistent feeling of needing to pass stool even when the bowels are empty. This constant urge results from the enlarged tissue pressing against the rectal wall, which the visceral nerves interpret as a requirement for evacuation. This feeling of incomplete emptying can be a continuous source of minor discomfort.
When Sensation Changes Due to Prolapse
The experience of internal hemorrhoids changes significantly when they prolapse, meaning they protrude outside the anal opening. This protrusion introduces discomfort and pain, as the tissue moves below the dentate line. The tissue below this line is supplied by somatic nerves, which detect pain, touch, and temperature. Once exposed, the prolapsed tissue becomes subject to irritation from clothing, friction, and mucus discharge.
This can lead to localized, sharp discomfort, a palpable lump, and intense itching known as pruritus ani. Pain is often noticeable during or immediately following a bowel movement, or while sitting for long periods. Severe, constant, throbbing pain can occur if the prolapsed hemorrhoid becomes strangulated, meaning the anal muscles cut off its blood supply. Similarly, thrombosis, the formation of a blood clot, results in sudden, severe pain and a hard, tender lump that requires immediate medical attention.
Identifying Internal Versus External Symptoms
The type of sensation experienced is the clearest way to differentiate between internal and external hemorrhoids. Internal hemorrhoids, residing in the upper anal canal, are primarily associated with painless bleeding and feelings of pressure. Pain only becomes a factor if the internal tissue prolapses or if complications like thrombosis develop. In these cases, the pain is linked to the exposure of the tissue to the sensitive area below the dentate line.
External hemorrhoids, which originate under the skin around the anal opening, are painful from the onset because this area is richly supplied with somatic, pain-sensing nerves. The primary complaint for external hemorrhoids is acute, constant pain, tenderness, and swelling. When an external hemorrhoid develops a blood clot, the resulting thrombosed external hemorrhoid causes a sudden, hard, and intensely painful lump. Therefore, sharp, constant pain is a much more common initial symptom of an external, rather than an uncomplicated internal, hemorrhoid.