The most serious acute complication of a colostomy is stoma necrosis, where the tissue of the stoma loses its blood supply and begins to die. This occurs in up to 13–16% of patients and, if the damage extends deep enough, requires emergency surgery. Left untreated, full-thickness necrosis can lead to peritonitis (a life-threatening abdominal infection), bowel perforation, and sepsis.
That said, colostomy complications span a wide range of severity and timing. Some appear within hours of surgery, others develop months or years later. Understanding which complications are urgent, which are common, and what warning signs to watch for can make a real difference in outcomes.
Stoma Necrosis: The Most Dangerous Early Complication
Stoma necrosis happens when the segment of bowel brought through the abdominal wall doesn’t receive enough blood. The most common cause is damage to the blood vessels that feed that section of intestine during surgery, whether from tying off a key artery, stripping too much of the tissue that carries blood vessels to the bowel, or creating too much tension when pulling the bowel through the abdominal wall. It’s most frequently seen with colostomies (as opposed to ileostomies), in patients who are obese, and in people who needed emergency surgery rather than a planned procedure.
Signs typically appear within the first 24 hours after surgery. A healthy stoma is pink or red and moist. When blood supply is compromised, the stoma may turn dusky, dark purple, or black. It’s worth noting that some mild discoloration right after surgery is normal. Swelling can temporarily restrict blood drainage, causing the stoma to look purplish, but this usually resolves as swelling goes down and the tissue returns to a healthy pink-red color.
The critical distinction is between superficial and deep necrosis. If the tissue damage stays at the surface level and above the muscle layer of the abdominal wall, it can often be monitored closely and may lead to narrowing of the stoma later on. But if necrosis extends below the fascia (the tough connective tissue layer of the abdominal wall), urgent reoperation is required. Surgeons assess the depth using a scope, a clear tube with a light, or by checking blood flow with a needle. Full-thickness necrosis that extends more than 1 to 2 centimeters deep typically calls for early surgical revision to prevent the stoma from scarring shut later.
Parastomal Hernia: The Most Common Long-Term Problem
While necrosis is the most dangerous complication in the short term, parastomal hernia is by far the most common structural problem over time. A bulge develops around the stoma as abdominal contents push through the weakened muscle opening. Reported incidence runs as high as 78% depending on the type of stoma and how long patients are followed.
Many parastomal hernias cause no symptoms at all. When they do require surgical repair, the most common reasons are intestinal obstruction (about 27% of repair cases), pain around the stoma (26%), recurring obstructive symptoms (12%), and leakage from the ostomy appliance because the hernia distorts the skin surface (12%). The concern with any hernia is incarceration, where a loop of bowel gets trapped in the hernia and its blood supply is cut off. This is a surgical emergency.
Prolapse and Retraction
Stoma prolapse occurs when the bowel telescopes outward through the stoma opening, sometimes protruding several inches. This happens in 2% to 10% of colostomy patients overall, but the rate jumps to as high as 30% for transverse loop colostomies. Colostomies are significantly more prone to prolapse than ileostomies. Risk factors include older age, obesity, chronic lung disease (which increases abdominal pressure from coughing), and surgical technique. Placing the stoma through the rectus abdominis muscle rather than between muscles dramatically reduces prolapse rates: one study found a 2.4% prolapse rate through the muscle versus 26.5% when placed between muscles.
Stoma retraction is the opposite problem. The bowel pulls back below the skin surface, making it difficult to attach an appliance and divert stool properly. It occurs in 1% to 6% of cases and is usually caused by insufficient mobilization of the bowel during the original surgery or by ischemia that causes the tissue to shrink. Retraction is one of the most common reasons patients need a second operation on their stoma. With a loop colostomy, retraction can mean stool isn’t fully diverted, defeating the purpose of the colostomy.
Loop vs. End Colostomy Complications
The type of colostomy matters. Loop colostomies, where a loop of bowel is brought to the surface and opened, carry higher rates of delayed complications compared to end colostomies, where the bowel is divided and a single end is brought through. In one study, delayed complications like prolapse, retraction, and fistula occurred in 26% of loop colostomy patients compared to 7% of end colostomy patients. Five loop stomas in that study eventually needed to be converted to end stomas because of ongoing problems. Early complication rates, however, were not significantly different between the two types.
Peristomal Skin Damage
Up to 80% of people with an ostomy will experience some form of skin complication around the stoma. The most common is irritant contact dermatitis, where repeated exposure to digestive secretions or stool causes inflammation, redness, and sometimes raw, broken skin. Ileostomy patients tend to have more skin problems than colostomy patients because ileostomy output is more liquid and contains more digestive enzymes, but colostomy patients are far from immune.
Skin damage may sound minor compared to necrosis or hernias, but chronic peristomal irritation significantly affects quality of life. It makes appliance adhesion unreliable, which leads to more leakage, which worsens the skin damage in a frustrating cycle. Proper appliance fit and skin barrier products are the primary tools for managing this.
Warning Signs That Need Immediate Attention
Certain changes around a colostomy signal a potential emergency. A stoma that turns very dark red, purple, or black may be losing its blood supply and needs same-day evaluation. A complete stop in stoma output, especially combined with abdominal cramping or vomiting, can indicate bowel obstruction. A rapidly enlarging bulge around the stoma that becomes painful and firm may signal an incarcerated hernia.
A healthy stoma is consistently moist and some shade of pink to red, similar to the inside of your cheek. It has no nerve endings, so the stoma itself doesn’t hurt. Pain localized around the stoma site, rather than at the stoma itself, often points to a complication in the surrounding tissue or abdominal wall. Any sudden change in the stoma’s appearance, output, or the comfort of the surrounding skin is worth getting checked promptly rather than waiting for a scheduled appointment.