At a glance
Hemorrhoids are one of the most common health conditions, yet widely misunderstood. They are not a disease — hemorrhoidal tissue is a normal part of human anatomy. The condition people refer to as “hemorrhoids” develops when this normal tissue becomes enlarged, swollen, or symptomatic.
This guide explains what hemorrhoids actually are, why they develop, and the factors that make some people more susceptible.
What hemorrhoidal tissue is
Inside the anal canal, there are clusters of blood vessels, connective tissue, and smooth muscle known as hemorrhoidal cushions. Everyone has them. They serve important functions:
- Continence — they help seal the anal canal, contributing to fine control
- Cushioning — they protect the anal canal during bowel movements
- Sensation — they contain nerve endings that contribute to the sensory discrimination between gas, liquid, and solid
These cushions are supplied by branches of the rectal arteries and drained by the rectal veins. The blood flow through them is what makes them cushion-like — they are naturally engorged with blood.
What goes wrong
Hemorrhoids become symptomatic when:
- The blood vessels enlarge — increased pressure causes the veins to swell beyond their normal size
- The supporting tissue weakens — the connective tissue and smooth muscle that hold the cushions in place stretch and degrade
- The cushions prolapse — they descend from their normal position inside the anal canal, sometimes protruding through the anus
This process is similar to varicose veins elsewhere in the body — blood vessels stretch under sustained pressure, and the supporting structures gradually weaken.
Types of hemorrhoids
Internal hemorrhoids
Located above the dentate line (a boundary inside the anal canal). The tissue here has limited pain sensation, which is why internal hemorrhoids often present with painless bleeding rather than pain.
Internal hemorrhoids are graded by severity:
- Grade 1 — enlarged but do not prolapse
- Grade 2 — prolapse during straining but return on their own
- Grade 3 — prolapse and need to be pushed back manually
- Grade 4 — permanently prolapsed
External hemorrhoids
Located below the dentate line, under the skin around the anus. This tissue has significant pain sensation, which is why external hemorrhoids — particularly thrombosed ones — can be intensely painful.
Why hemorrhoids develop
The pressure factor
The primary driver is increased pressure on the hemorrhoidal veins:
- Straining during bowel movements — the most common and most modifiable factor
- Constipation — hard stools require more effort to pass
- Prolonged toilet sitting — the design of a toilet seat means unsupported pressure on the hemorrhoidal area
- Heavy lifting — increases intra-abdominal pressure
- Pregnancy — the growing uterus compresses pelvic veins
The structural factor
The supporting tissues weaken over time:
- Ageing — the connective tissue degrades naturally, which is why hemorrhoids become more common with age
- Genetics — some people inherit weaker connective tissue
- Repeated straining — the cumulative effect of years of constipation and straining
Contributing factors
- Diet — low fibre intake leads to harder stools and more straining
- Dehydration — insufficient water intake affects stool consistency
- Sedentary lifestyle — prolonged sitting and reduced physical activity
- Obesity — increased intra-abdominal pressure
- Chronic cough — sustained increased abdominal pressure
- Pregnancy and childbirth — hormonal changes, increased blood volume, and the mechanical pressure of the growing uterus
The reassuring perspective
Hemorrhoids are:
- Extremely common — affecting a significant proportion of adults at some point
- Not dangerous — they are not cancerous and do not lead to cancer
- Treatable — from dietary changes to medical procedures, effective options exist at every severity level
- Often preventable — addressing the modifiable factors (diet, hydration, toilet habits) can reduce both occurrence and recurrence
Understanding what hemorrhoids are and why they develop is the first step toward managing them effectively.