A colostomy stoma is a surgically created opening on the surface of your abdomen where part of the large intestine (colon) is brought through the abdominal wall so that stool can leave your body without passing through the rectum and anus. The surgeon pulls the colon through a hole in the skin and muscle, then stitches the intestine directly to the skin, forming a new exit point for waste. A pouch worn on the outside of the body collects the output.
What a Stoma Looks Like
A stoma is a roundish opening, typically one to two inches wide. It’s pink or red and looks like moist tissue, similar to the inside of your mouth. Some stomas lie flat against the skin, while others stick out slightly. Right after surgery, the stoma appears swollen and may ooze small amounts of blood for the first few days. Over the following two to three months, it shrinks considerably to its permanent size. During that period, you’ll need to measure it regularly so your pouching supplies fit correctly.
One detail that surprises many people: a stoma has no nerve endings. You can’t feel it being touched. Once the surgical site heals, you shouldn’t feel the stoma itself at all, though the skin around it can still be sensitive.
Why a Colostomy Is Performed
Several conditions can lead to colostomy surgery. The most common include colorectal cancer (especially when the rectum needs to be removed), complications from diverticulitis, inflammatory bowel disease, and traumatic injury to the colon or rectum. It may also be done for intestinal blockages, abnormal connections between the bowel and skin called fistulas, or birth defects like an absent anal opening.
In some cases, the colostomy is temporary. The surgeon diverts stool away from a section of bowel that needs time to heal after injury or surgery, then reconnects the intestine weeks or months later. In other cases, particularly when the rectum is removed due to cancer or the muscles controlling bowel function have failed, the colostomy is permanent.
End Colostomy vs. Loop Colostomy
There are two main structural types. An end colostomy creates a single stoma that protrudes slightly above the skin. The downstream portion of the colon is either removed or sealed off. This type is more often permanent and is common after surgery for rectal cancer.
A loop colostomy pulls a loop of colon through the abdominal wall, creating what looks like one large stoma but actually has two openings: one that passes stool and one that releases only mucus. Loop colostomies are typically temporary, designed to let the bowel heal before the surgeon reverses the procedure and restores normal function.
How Stoma Location Affects Output
Where the stoma sits along the colon makes a real difference in what comes out of it. The colon’s primary job is absorbing water from digested food, and it does this progressively as material moves along its length. A stoma placed in the transverse colon (the section running across the upper abdomen) produces softer, less formed stool because the waste hasn’t traveled far enough for much water to be reabsorbed. A stoma in the descending or sigmoid colon (the left side and lower portion) produces output that’s closer to normal stool in consistency, since most of the water absorption has already happened.
This distinction matters for daily management. People with a sigmoid colostomy may eventually develop somewhat predictable bowel patterns, while those with a transverse colostomy generally deal with looser, more frequent output.
The Pouching System
Stool leaving the stoma is collected in a pouching system that attaches to the abdomen. Every system has two basic components: a skin barrier (also called a wafer) that sticks to the skin around the stoma and creates a seal, and a pouch that collects the output.
One-piece systems combine the wafer and pouch into a single unit. They feel streamlined but require removing and replacing the entire system, barrier included, at each change. Two-piece systems let you swap the pouch while leaving the skin barrier in place, which can reduce irritation from repeatedly peeling adhesive off the skin. The pouch snaps or clips onto the barrier’s flange.
Pouches also come in two styles. Drainable pouches open at the bottom so you can empty them while still wearing them, then reseal with a clip or built-in closure. Closed-end pouches are sealed at the bottom and discarded after a single use. For colostomies that produce firmer, less frequent output, closed-end pouches are often practical. The skin barrier itself can be flat or convex (curved inward), depending on whether the stoma sits flush with the skin or protrudes enough for a flat seal to work.
Skin Irritation Around the Stoma
The skin surrounding the stoma, called peristomal skin, is vulnerable to irritation. Studies report that roughly 7 to 20 percent of colostomy patients develop peristomal skin complications, with some research finding rates as high as 35 percent within the first 90 days after surgery. Colostomy patients fare better than those with ileostomies (small intestine stomas), whose more liquid, enzyme-rich output causes higher rates of skin breakdown.
The most common problem is irritant dermatitis, caused by stool leaking under the skin barrier. A poorly fitting wafer, a stoma that has changed size, or skin folds near the stoma can all break the seal. Keeping the barrier opening properly sized to your stoma, especially during those first months when it’s still shrinking, is one of the most effective ways to prevent skin problems.
Possible Complications
Beyond skin irritation, several structural complications can develop over time. A parastomal hernia occurs when a section of bowel pushes through the abdominal wall next to the stoma, creating a visible bulge around it. This is the most common long-term complication, and in many cases the only noticeable symptom is the deformity itself. Small hernias may need no treatment beyond a support belt, while larger ones can require surgical repair.
Stoma prolapse happens when the bowel telescopes outward through the stoma, making it appear significantly longer than usual. It can look alarming but isn’t always an emergency. Retraction is the opposite problem: the stoma sinks below skin level, making it difficult for the pouching system to form a proper seal and increasing the risk of leaks and skin irritation. Both conditions sometimes require surgical correction.
Foods That Need Extra Caution
Most people with a colostomy can eat a wide variety of foods, but certain high-fiber items can cause blockages, particularly in the early weeks after surgery. Foods high in insoluble fiber or tough cellulose need to be eaten in small amounts and chewed thoroughly. The common culprits include raw vegetables, unpeeled fresh fruits, corn, mushrooms, coconut, nuts, seeds, popcorn, dried fruits, celery, cabbage, and meats in casings like hot dogs. Bran and high-fiber grains such as granola also warrant caution.
A blockage at the stoma typically starts with very watery stool spurting almost constantly (liquid squeezing past the obstruction), bloating, cramping, and strong odor. The stoma or surrounding skin may swell. If the blockage doesn’t resolve, stool output stops entirely, and nausea or vomiting follows. Introducing high-fiber foods gradually and in small portions lets you identify which ones your body handles well.