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Are You IBD Aware? Crohn's and Colitis, Explained

Medically reviewed by Carmen Fookes, BPharm. Last updated on Feb 7, 2022.

Crohns And Colitis: Notable Differences

Crohn's Disease and Ulcerative Colitis (UC) (often abbreviated to colitis) both affect the intestine. But what is the difference between them?

In Crohn's disease, only certain parts of the intestine are affected. Inflamed areas exist in patches, and may be located anywhere between the mouth and the anus. The inflammation also tends to extend through multiple, if not all, layers of the bowel wall. However, significant areas of the intestine remain healthy.

UC affects only the inner most lining of the colon. Although the colon is the only part of the bowel affected, the whole of the colon is inflamed.

Crohns And Colitis: Significant Similarities

Symptoms are so similar with both disorders that a doctor cannot tell if you have Crohn's or UC based on symptoms alone. Further medical investigations are needed.

Both conditions affect men and women equally and most people are diagnosed during their teenage years, although the disease can occur at any age. Despite extensive research, the cause of both Crohn's and UC remains elusive. However similar environmental factors (such as stress, pollution, and lifestyle) have been associated with both diseases, and they are known to run in families. Interestingly, smoking is associated with a worse prognosis for people with Crohn's disease, but not for those with UC.

Both are considered autoimmune conditions and are classified under the umbrella term "Inflammatory Bowel Disease" (IBD). One in ten people with IBD display features of both Crohn's disease and UC and are usually diagnosed with indeterminate colitis. Medications used to treat both conditions are similar, with a few exceptions.

Although there is no evidence that diet causes IBD, attention to diet post-diagnosis may reduce symptoms and promote healing.

Crohn's Disease: Cause Still Elusive

Crohn's disease was first described in 1932 by Dr. Burrill B. Crohn, (who gave the disease his name) and his two colleagues Dr. Leon Ginzburg and Dr. Gordon D. Oppenheimer.

Although it can affect any part of the digestive tract, it more commonly affects the area where the ileum (small intestine) joins the colon (large intestine).

More than 780,000 Americans are estimated to have Crohn's disease and research shows the disease runs in families and is more prevalent among the Eastern European Jewish population.

Doctors do not know exactly what causes Crohn's disease, but for some reason the immune system is activated in response to harmless substances such as food, beneficial bacteria, or the intestinal tissue itself. Activation of the immune system leads to the release of various chemicals and defensive white blood cells which in turn create an inflammatory response in the intestines. Affected areas of intestinal tissue may ulcerate, creating shallow or deep crater-like sores, fissures, and cracks that may link together in a cobblestone-like pattern. Abscesses (pockets of pus) can also develop. Diet and stress may aggravate the disease, but are not the cause. Crohn’s disease is more common in "Westernized" countries, Northern latitudes, urban areas and in people who smoke. Links between Crohn's disease and lack of sunlight or vitamin D, and reduced exposure to beneficial bacteria during childhood, have also been explored but no firm conclusions made.

Crohn's Disease: Symptoms

Most people with Crohn's find it hard to pinpoint the time when they first developed symptoms. Many recall a certain stressful event (death of a pet, change in school, house move) leading up to their diagnosis, or a history of always having a "sensitive stomach". Once diagnosed, several remember previous clusters of symptoms, perhaps wrongly attributed to "stomach bugs".

The majority of people with Crohn's disease have periods of active, symptomatic disease and periods of remission (no symptoms at all).

The most common symptoms associated with Crohn's include diarrhea that persists for several weeks, abdominal pain and weight loss. Around 50% notice blood or mucus in their feces and some may report an urgent need to move their bowels or a sensation of incomplete evacuation. Occasionally, constipation can occur that can lead to bowel obstruction (a blockage of the bowel). Severe Crohn's can result in painful anal tears (fissures) and fistulas - tunnels that connect one part of the intestine to another or to other organs such as the bladder or skin. Nonspecific symptoms of Crohn's include fever, fatigue, loss of energy, night sweats, and poor appetite.

Treating Crohn's Disease: Softly Does It Or Hit 'Em Hard?

Treatment for Crohn's disease is tailored to each individual and includes medication, dietary restrictions, and sometimes surgery to remove diseased parts of the intestinal tract.

Although there is no cure for Crohn's disease, the development of new therapies, particularly biologics, has greatly improved remission rates and duration of remission.

Some doctors treat patients using a "step-up" approach. Initial therapy usually consists of dietary modifications together with milder drugs such as 5-aminosalicylates (5-ASAs) (includes drugs such as sulfasalazine, [Azulfidine], mesalamine [Asacol, Pentasa], olsalazine [Dipentum]), and antibiotics. However, the use of 5-ASAs is not without controversy as only a small proportion of patients appear to benefit. For those patients who do not respond, corticosteroids such as prednisone or budesonide, or immunomodulators, such as azathioprine or methotrexate may be used. Biologic agents (infliximab, adalimumab, certolizumab, natalizumab, vedolizumab) and surgery are also options. Ustekinumab (Stelara) is another treatment that may be considered in people who are intolerant of or who have failed to respond to standard therapy.

The Guns Blazing (Top Down) Approach

Hitting the disease hard with more potent and aggressive drugs (the "Top Down" approach) seems to work best for patients who present with moderate-to-severe type disease.

Biologic agents (infliximab, adalimumab, certolizumab, natalizumab, vedolizumab) may be given with steroids as needed or in combination with immunomodulator drugs such as azathioprine.

Several trials support using a combination approach, although doctors should be wary of over-treatment. Patients more suited to "Top Down" therapy include those who are younger, with upper gastrointestinal tract involvement, smokers, or those with complications or other poor prognostic indicators.

Important Points About Biologics

Biologics have been available since 1998 when infliximab (Remicade) became the first TNF-inhibitor approved to treat moderate-to-severe Crohn's that had not responded to other therapies. Since then, several other biologics have been approved, including: adalimumab (Humira), certolizumab (Cimzia) and natalizumab (Tysabri). While all work to disrupt chemical messaging systems between immune cells, each one differs in its composition and schedule of administration. Many are also used to treat other inflammatory conditions, such as Rheumatoid Arthritis.

Some doctors believe more patients could be helped by biologics sooner than currently recommended. But they are not without their side effects. Infection is the main concern, because they all suppress the immune response.

A boxed warning for an increased risk of infections that could lead to hospitalization or death applies to Cimzia, Humira, and Remicade. TNF inhibitors are also not recommended for people with heart failure, multiple sclerosis, or tuberculosis, as they may worsen these conditions. TNF inhibitors have also been linked to a higher incidence of lymphoma, a type of cancer that affects the immune system. Common side effects of biologics include flu-like symptoms, headache, nausea, rash and injection-type reactions.

Ustekinumab (Stelara): Another Weapon In The Fight Against Crohn's and Ulcerative Colitis

Stelara (ustekinumab) was FDA approved in 2016 to treat Crohn's disease in adults who have not responded to standard treatments such as immunomodulators and corticosteroids or TNF blockers, or who are intolerant of them.

It is the first biologic therapy that targets both interleukin (IL)-12 and IL-23 cytokines, which underlie inflammatory and immune responses. Stelara is initially administered IV by a health professional, although subsequent doses can be self-injected subcutaneously every eight weeks by the patient after proper training. Dosing is weight-based. It is the first treatment to improve the intestinal lining, rather than just dampening down inflammation.

34-56% of patients reported relief from their Crohn's symptoms six weeks after a one-time IV dose of Stelara. Many reported a noticeable improvement after three weeks. The majority who carried on with Stelara treatment were in remission after 52 weeks.

In October 2019, the FDA extended approval of Stelara to adults with moderately-to-severely active Ulcerative Colitis. 58% of patients experienced a clinical response at Week 8 in one trial, with 19% achieving clinical remission. By one year, 45% of patients were in remission; the majority of those without the use of corticosteroids.

Ulcerative Colitis: Symptoms and Cause

As previously said, symptoms of Ulcerative colitis (UC) are similar to those of Crohn's disease. In fact, without further investigations, a definite distinction cannot be made.

Diarrhea and the frequent need to have a bowel movement (also called tenesmus) is the predominant symptom. Pus and mucus may also occur as a result of ulcers that form in the colon. Other symptoms include rectal bleeding or bloody stools, abdominal pain, tiredness, and loss of appetite.

Like Crohn's disease, the cause remains unknown although an abnormal immune response seems responsible for the inflammation, and diet and stress aggravate the condition. Genetics also seem to play a role.

Treatment Of UC - Medications Relieve Inflammation

Corticosteroids (such as prednisone, budesonide, and hydrocortisone) and 5-aminosalicylates (5-ASAs) (such as sulfasalazine, mesalamine) help to relieve mild symptoms of UC. These can be given in oral or rectal form, depending on availability. The rectal form is particularly suited to patients whose disease occurs in the rectum alone (referred to as proctitis) or slightly further up where enemas can still reach.

Antidiarrheal agents such as loperamide are used in addition to other treatments to better manage diarrhea. Dehydration is a common consequence of diarrhea and people with UC should drink plenty of water throughout the day to combat this.

Approximately 15% of UC patients have severe disease and doctors may prescribe immunomodulators (such as azathioprine), cyclosporine, or biologics in an effort to control the disease.

Biologics, such as infliximab (Remicade), are highly effective in UC; however, 40% of patients fail to respond and, of those who do respond, 30-40% lose response to infliximab over time.

Other biologics used to treat UC include adalimumab (Humira), golimumab (Simponi), and vedolizumab (Entyvio).

In 2018, tofacitinib (Xeljanz) became the first oral drug to be approved for chronic use to treat adults with moderately to severely active ulcerative colitis (other agents must be administered through an intravenous infusion or subcutaneous injection). Tofacitinib blocks the activity of certain enzymes in the body that affect immune system function and is not recommended for use in combination with biologics or potent immunosuppressants, such as azathioprine. An extended-release form, Xeljanz XR was approved in December 2019, giving patients the option of a once-daily treatment.

Other drugs, such as etrolizumab, are still undergoing clinical trials. Researchers are also looking into other compounds, including one that reduces the activity of a gene linked to blood clotting, and reduces symptoms of inflammatory bowel disease without directly targeting inflammation.

Intestinal Diseases That Affect More than Just the Intestines

Unfortunately for a significant proportion of patients with Crohn's disease or UC, the consequences of having an immune system that doesn't behave as it should are felt in other organs of the body. Extraintestinal manifestations (EIM) affect 25-40% of people with IBD and can affect nearly any organ system, including the skin, eyes, muscles, joints, liver and kidneys.

Some patients, particularly children, develop EIM prior to intestinal symptoms, which can make the initial diagnosis more challenging. 25% of patients with IBD develop more than one EIM.

Musculoskeletal pain is the most common EIM and other more common manifestations include arthritis, skin conditions, such as erythema nodosum and pyoderma gangrenosum, primary sclerosing cholangitis (an inflammatory disorder that affects the bile ducts), nephrolithiasis, and episcleritis (an inflammation of the thin membrane that covers the white of the eye).

Use of Surgery In Ulcerative Colitis Or Crohn's Disease

The decision to perform surgery in people with either UC or Crohn's disease is based on several factors including: a patient's quality of life, the extent of their disease, and the effectiveness of their current medication. Surgery may be an absolute necessity for some people, whereas others may be given the option to choose surgery as part of their treatment plan. Surgery may also be recommended to reduce the risk of colorectal cancer.

Surgery usually involves removal of the diseased segment of bowel (called a resection) before joining the two ends of healthy bowel together. Up to 23-45% of people with UC and 75% of people with Crohn's disease eventually require surgery. It is not without its risks, so doctors carefully screen patients for suitability. Surgery is not considered a cure, and particularly for Crohn's patients, the disease frequently recurs even after remission periods of several years.

A sudden, severe attack of UC which fails to respond to even intravenous steroids is the main reason for surgery for UC. Severe attacks of UC can lead to toxic megacolon (a rapid enlargement of the colon), uncontrolled bleeding, or a perforation in the colon (holes in the wall of the intestine) - all of which can be life-threatening.

Surgery may be needed in people with Crohn's disease who develop strictures (narrowing of the intestine due to scar tissue) or blockages; perforations; excessive bleeding; fistulas (unwanted tunnels made of tissue that drain mucus or stool into another area of the body); abscesses; or toxic megacolon.

Colorectal Cancer Risk

The risk of developing colorectal cancer (CRC) is higher in people with Crohn's disease and UC compared with the general population. People who have had either Crohn's or UC for more than eight to ten years, or whose disease affects most of their colon, are more at risk.

Although most cases of CRC in people without IBD start off with a precancerous polyp (a small, stalked lump that grows out from the intestinal wall), this is not always the case for people with Crohn's or UC. Precancerous areas of tissue (dysplasias) may lie flat against the intestinal wall, or precancerous cells may be hidden within normal tissue. A series of small biopsies taken during a colonoscopy is the only way to identify potential cancerous areas. Surveillance colonoscopies are recommended every one to two years in people who have had IBD for more than eight to ten years.

Diet And Nutrition

It's not surprising that dehydration and malnutrition are common in people with either Crohn's disease or UC. During active periods of disease, inflammation and diarrhea affect fluid and nutrient absorption and contribute to a reduced appetite.

Although foods do not cause IBD, certain foods can aggravate either Crohn's or colitis. It is a good idea to pay attention to avoiding foods that worsen or trigger YOUR symptoms, as there is no one diet that is recommended by the Crohn's and Colitis Foundation of America. Keeping a food journal - a diary of what, how much, and when you eat and any associated symptoms - may help. At the same time as restricting certain foods, it is important to maintain good nutrition. Dietary choices may become somewhat complicated.

Fiber is essential for health and digestion, but has been associated with cramping, bloating and more severe diarrhea when consumed by people with IBD. Fiber exists as soluble (able to be dissolved in water) and insoluble fiber. While most fruit and veges contain both soluble and insoluble fiber; cooking or peeling can help reduce their insoluble fiber content. Improving soluble fiber intake can help reduce diarrhea by slowing down how fast food transits through the intestine.

Wholemeal grains and foods such as beans, fruit, green leafy vegetables, nuts, seeds, and wheat bran should be limited in favor of foods such as cooked, pureed, or canned vegetables and fruit. Foods that are easier to digest, such as potatoes, asparagus, applesauce and melons also improve soluble fiber intake. 80% of children in a small study reported an easing of IBD symptoms following 12 weeks of a diet containing nutrient-rich foods such as fruits, vegetables, and meat, but which lacked grains, most dairy products, processed foods, and sugars, except for honey.

Other Foods To Eat....Or Not To Eat

Inflammation in the ileum (lower part of the small intestine) can limit the absorption of fatty and greasy food. Gas and diarrhea may be more problematic if high-fat foods such as butter, margarine, and cream are eaten.

Gluten (found in wheat, rye, barley and some oats) may also aggravate either Crohn's or UC in people with gluten sensitivities or intolerance. Testing for Celiac disease is also recommended, as Celiac disease is more common in people with IBD.

Sugar substitutes, such as sorbitol and mannitol may cause diarrhea, bloating and gas. Sorbitol is also found naturally in some fruits - such as apples, pears, peaches and prunes - and in icecream.

Protein is an important part of everybody's diet but people with IBD should choose protein sources lower in fat such as fish, white poultry, lean ground beef, tofu, and eggs. Red meat and darker poultries are best avoided.

Crohn's And Colitis Foundation of America

Living with an incurable disease can be challenging, but for people with Crohn's or UC, the approval of a range of biologics over the past few years and the promising early results of new drugs in the pipeline is good news.

Good support and information is available through the Crohn's and Colitis Foundation of America. Their website lists local support groups and events especially for people and family members living with IBD. also hosts a Crohn's disease support group and an Ulcerative Colitis support group.

Finished: Are You IBD Aware? Crohn's and Colitis, Explained

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