Hemorrhoids are cushions of blood vessels that naturally line your anal canal, and their job is to help you control your bowel movements. Everyone has them. They become a problem only when they swell, stretch, or slip out of position, which is when they cause bleeding, pain, itching, or visible lumps. The word “hemorrhoids” usually refers to this swollen, symptomatic state, but the tissue itself serves an important purpose.
Their Normal Job in Your Body
Your anal canal contains three columns of cushioned tissue made up of blood vessels and connective fibers. These cushions do two things. First, they help with continence, meaning they create a seal that helps you hold in stool and gas until you’re ready to go. Second, they protect the ring of sphincter muscles that give you the ability to delay a bowel movement so you can make it to a bathroom. During a normal bowel movement, these cushions fill with blood, cushion the canal walls, and then deflate. When something disrupts this cycle, the tissue stays swollen and symptoms begin.
What Happens When They Swell
When hemorrhoidal tissue swells beyond its normal size, it behaves differently depending on whether it’s inside the rectum or at the outer edge of the anus.
Internal hemorrhoids sit inside the rectum, lined with tissue that has no pain-sensing nerves. That’s why they can bleed without hurting. The most common sign is small amounts of bright red blood on toilet paper or in the bowl after a bowel movement. The blood is bright red because it comes from vessels very close to the surface and hasn’t traveled far through the digestive tract. Many people with early internal hemorrhoids have no idea they’re there until they notice the bleeding.
External hemorrhoids sit just outside the anal opening, covered by skin that is rich in pain-sensing nerves. Most of the time, external hemorrhoids don’t cause symptoms unless a blood clot forms inside one. When that happens (called thrombosis), the result is a sudden, hard, painful lump. Pain is typically most intense in the first 48 hours.
How Internal Hemorrhoids Progress
Internal hemorrhoids are classified on a four-grade scale based on how far they’ve moved from their normal position.
- Grade 1: Slightly enlarged veins that stay inside the rectum. You can’t see or feel them externally. Painless bleeding is the main symptom.
- Grade 2: Larger swelling that pushes outside the anus during straining or, less commonly, physical activity. They slide back inside on their own once the pressure stops.
- Grade 3: Similar to grade 2, but they no longer retract on their own. You have to push them back in manually.
- Grade 4: Permanently prolapsed outside the anus and cannot be pushed back in at all. These carry the highest risk of complications.
Bleeding, Itching, and Mucus
Bleeding is the hallmark symptom of internal hemorrhoids. It happens when hard stool scrapes the thin, stretched surface of the swollen cushion, or when straining puts enough pressure on engorged vessels to rupture them. Because the tissue inside the rectum lacks pain nerves, the bleeding is typically painless.
Itching around the anus is another common effect, and it has a specific cause. When internal hemorrhoids prolapse (slide outside), they secrete mucus and can allow small amounts of stool to leak onto the surrounding skin. That moisture and irritation triggers the persistent itch known as pruritus ani. Keeping the area clean and dry helps, but the itch won’t fully resolve until the prolapse is addressed.
When a Blood Clot Forms
A thrombosed hemorrhoid is an external hemorrhoid in which blood has pooled and clotted. It produces a firm, bluish lump at the edge of the anus that can be intensely painful to sit on, walk with, or touch. The acute pain peaks within the first two days and then gradually decreases over the following week or two as the clot is reabsorbed. Once a thrombosed hemorrhoid resolves, it sometimes leaves behind a small flap of excess skin (a skin tag) that can cause mild irritation or make cleaning after a bowel movement more difficult.
What Makes Them Flare
Anything that increases pressure inside the abdomen or around the anal canal can push hemorrhoidal tissue past its tipping point. The most common triggers share a single theme: sustained downward force on the pelvic floor.
Straining during bowel movements is the biggest driver. Constipation, low-fiber diets, and sitting on the toilet for long stretches all keep that pressure elevated. Pregnancy is another major factor because hormonal changes loosen blood vessel walls while the growing uterus adds direct pressure to the pelvic veins. Vaginal delivery compounds this with intense straining. Heavy lifting, chronic coughing, and obesity can also contribute. Reducing straining during bowel movements has a direct effect: it shrinks the swollen veins and reduces symptoms.
How Symptoms Typically Feel
The experience varies a lot depending on the type and severity. Early internal hemorrhoids may produce nothing more than occasional streaks of blood and a vague sense of fullness in the rectum. As they progress, you might feel tissue bulging out during a bowel movement, along with a dull ache or pressure that lingers afterward. Prolapsed hemorrhoids can create a constant awareness of something being “there,” combined with moisture, itching, and difficulty getting fully clean.
External hemorrhoids that aren’t thrombosed often feel like a soft, painless bump. But when a clot forms, the shift is dramatic: sudden sharp pain, swelling, and tenderness that makes sitting uncomfortable for days. The pain is disproportionate to the size of the lump, which can be as small as a pea or as large as a grape.
One thing hemorrhoids do not typically cause is deep abdominal pain, dark or tarry stool, or changes in bowel habits like persistent diarrhea or pencil-thin stool. Those symptoms point to other conditions further up the digestive tract and warrant a different evaluation.