Colitis

Colitis is inflammation that affects the inner lining of your colon (large intestine). When the colon becomes irritated or swollen, it can affect digestion and lead to symptoms like diarrhea, belly pain, and a sudden urge to have a bowel movement.

Some types of colitis improve quickly. Others, like ulcerative colitis, a type of inflammatory bowel disease (IBD), are long-term conditions that may require ongoing management. With the right support, many people with colitis can control their symptoms and live comfortably again.

Colitis isn’t just one condition—there are several types, each with different causes and treatments.

Common types include:

• Ulcerative colitis: This form of IBD causes inflammation and sores in the lining of the colon and rectum.
• Crohn’s disease: This type of IBD can affect any part of the digestive tract, including the colon.
• Indeterminate colitis: This form of IBD occurs when inflammation is present, but there isn’t enough information to classify it as ulcerative colitis or Crohn’s disease. It’s also called IBD-undetermined (IBD-U).
• Infectious colitis: Caused by bacteria, viruses, or parasites, this condition is often temporary.
• Ischemic colitis: This condition occurs when blood flow to part of the colon is reduced.
• Microscopic colitis: This kind of inflammation can only be seen under a microscope and often leads to ongoing watery diarrhea.
• Medication-induced colitis: Certain medications that irritate the colon can cause this condition.

Colon inflammation can show up in different ways. Common signs include:

• Diarrhea, sometimes with blood or mucus
• Abdominal pain or cramping
• Rectal pain
• A sudden or urgent need to use the bathroom
• Feeling like you still need to go even after a bowel movement
• Fatigue
• Weight loss or lower appetite than usual
• Fever

Colitis develops when the lining of the colon becomes inflamed. This inflammation can happen for different reasons, and sometimes no single cause is identified.

In some cases, the immune system plays a role, either by overreacting or responding abnormally. This can lead to ongoing inflammation, as seen in IBD, or allergic reactions, which are more common in infants.

Colitis can also occur when the colon is irritated by external factors. Infections from bacteria, viruses, or parasites may trigger short‑term inflammation. Decreased blood flow to part of the colon can injure the tissue and lead to symptoms. Certain medications or medical treatments, including some antibiotics, nonsteroidal anti‑inflammatory drugs (NSAIDs), and cancer therapies, may also trigger or worsen inflammation.

Treatment depends on the type and severity of colitis. Medications often help reduce inflammation, control symptoms, or treat infections. Your doctor may also suggest diet and lifestyle changes, like staying hydrated, managing stress, or adjusting what you eat.

In some cases, procedures or surgery might be needed to remove damaged parts of the colon. Your team will work with you to find the approach that helps you get back to your usual self.

Not all types of colitis can be prevented, but you can take steps to lower your risk and reduce flare-ups:

• Follow a colitis diet that focuses on foods that are easier to digest and avoids your personal triggers
• Practice good handwashing and food safety to reduce the risk of infections that may cause an inflamed colon
• Take medications as prescribed to help control symptoms and inflammation
• Stay hydrated and eat a balanced diet
• Manage stress and get enough rest
• Quit smoking, if applicable
• Keep up with recommended vaccinations and regular checkups

Small changes can go a long way in helping you feel better day to day.

When you’re dealing with colitis, you want care that reflects what matters most to you. At Penn Medicine, you’ll work with specialists who treat every type of colitis. If you have a complex or long-term condition, the Inflammatory Bowel Disease (IBD) Care program connects you with a dedicated team focused on helping you manage symptoms, reduce flare-ups, and protect your long-term health.

Your care team takes the time to understand how colitis affects your routine, energy, and quality of life. Together, you’ll build a plan that feels realistic and supports your lifestyle so you can move forward with more confidence and fewer disruptions.