What is Crohn’s Disease?
Crohn’s disease is a lifelong condition where parts of the digestive system become inflamed. Crohn’s disease and ulcerative colitis are the two main disorders known collectively as inflammatory bowel disease (IBD), but IBD should not be confused with irritable bowel syndrome (IBS). Crohn’s disease affects people of all ages. The disease is an autoimmune disorder that occurs when the immune system, which usually fights infection, attacks the lining of the digestive tract, causing it to bleed and develop ulcers. The symptoms of the disease may be constant or may come and go every few weeks or months. When they return, it’s called a flare-up. Usually starting in childhood or early adulthood, the main symptoms are:
- Stomach aches and cramps
- Blood in your stools
- Tiredness (fatigue)
- Weight loss
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The disease, also called regional enteritis or regional ileitis, is a chronic inflammation of the digestive tract and usually occurs in the terminal portion of the ileum, the final section of the small intestine. There is no cure for Crohn’s disease, but many treatment options exist. The drugs used to help manage the condition, including steroids and antibiotics, aim to reduce inflammation. Since Crohn’s disease is an autoimmune disease, immunotherapy drugs known as biologics can also help ease inflammation, but these medications can have severe side effects.
Crohn’s disease was first described in 1904 by Polish surgeon Antoni Leśniowski. It was later named for American gastroenterologist Burrill Bernard Crohn, who, in 1932 in collaboration with others, published a thorough description of a then-unknown intestinal disorder they called regional ileitis.
Britannica.com describes Crohn’s as:
“Today, Crohn’s disease is characterised as a type of inflammatory bowel disease (IBD) and has been associated with abnormal function of the immune system and genetic variations. The disease also has been linked to abnormal changes in populations of intestinal bacteria. For example, Faecalibacterium prausnitzii, a normal inhabitant of the human intestinal tract, is found in decreased levels in people with Crohn’s disease, and Mycobacterium avium paratuberculosis, found in the intestinal tracts of ruminants affected by Johne’s disease, which is similar to Crohn’s disease in humans, has been isolated from the blood of some patients. However, despite these associations, the cause of Crohn’s disease remains unknown.”
Cause of Crohn’s Disease
While the precise causes of Crohn’s disease are unknown, it is believed to be caused by a combination of environmental, immune, and bacterial factors in genetically susceptible individuals. It results in a chronic inflammatory disorder, in which the body’s immune system defends the gastrointestinal tract, possibly targeting microbial antigens. Whilst Crohn’s is an immune-related disease, it does not appear to be an autoimmune disease (meaning the body itself is not triggering the immune system). However, the underlying immune problem is unclear and may be an immunodeficiency state. About half of the overall risk is related to genetics, with more than 70 genes involved. Tobacco smokers are twice as likely to develop Crohn’s disease as nonsmokers. It also often begins after gastroenteritis. Between 15 and 20% of people with Crohn’s have a relative with Crohn’s.
Diagnosis is based on several findings, including biopsy and appearance of the bowel wall, medical imaging, and description of the disease. Other conditions that can present similarly include irritable bowel syndrome and Behçet’s disease.
With no known cure for Crohn’s disease, treatment options (see below) are intended to help with symptoms, maintain remission, and prevent relapse. In newly diagnosed patients, a corticosteroid may be used briefly to rapidly improve symptoms, alongside another medication such as methotrexate or a thiopurine used to prevent a recurrence. Stopping smoking is recommended in people with Crohn’s disease.
One in five people with the disease is admitted to the hospital each year, and half of those with the disease will require surgery at some point over a ten-year period. While surgery should be used as little as possible, it is necessary to address some abscesses, certain bowel obstructions, and cancers. Checking for bowel cancer via colonoscopy is recommended every few years, starting eight years after the disease has begun.
Management of Crohn’s disease involves first treating the acute symptoms of the disease, then maintaining remission. Since Crohn’s disease is an immune system condition, it cannot be cured by medication or surgery. Treatment initially involves using medicines to eliminate infections (generally antibiotics) and reduce inflammation (generally aminosalicylate anti-inflammatory drugs and corticosteroids).
Surgery may be required for complications such as obstructions or abscesses or if the disease does not respond to drugs within a reasonable time. Surgery cannot cure Crohn’s disease and involves removing the diseased part of the intestine and rejoining the healthy ends, but the disease tends to recur after surgery. Once remission is induced, the goal of treatment becomes the maintenance of remission: avoiding the return of the active disease, or “flares”. Because of side effects, the prolonged use of corticosteroids is avoided. Although some people can maintain remission spontaneously, many require immunosuppressive drugs.
Forms of Crohn’s Disease and Symptoms
The various subforms of Crohn’s disease have not been recognised until recently. Historically, colonic Crohn’s disease was not distinguished from ulcerative colitis. Approximately 30 years ago, the first studies highlighted the diverse natural history of colonic and ileal Crohn’s disease. Inherent differences in disease behaviour (obstructing versus perforating) were later recognised by a group of physicians at Mount Sinai Hospital in New York.
Crohn’s disease is a chronic inflammatory disease mainly affecting the gastrointestinal tract. Some 115,000 people are living with Crohn’s in the UK. With no known cure, medical treatment aims to induce or maintain the absence of symptoms (remission). If symptoms are refractory (that is, resistant or unmanageable) to medication, surgical resection may be required. Post-surgical recurrence is common, with approximately 20-40% of patients requiring reoperation within ten years.
Inflammation caused by Crohn’s disease can involve different areas of the digestive tract in other people. This inflammation often spreads into the deeper layers of the bowel. Crohn’s disease can be both painful and debilitating and sometimes may lead to life-threatening complications.
Oral Crohn’s is a less common form of Crohn’s disease where ulceration occurs in and around the mouth – usually with some involvement of Crohn’s in the bowel. In oral Crohn’s, the affected site is the face and mouth.
Oral Crohn’s can occur on its own, and more than 60% on the first presentation do not have gut disease. Of those, over a ten-year period, approximately 30% will go on to develop gut symptoms. Most patients with oral Crohn’s developed it after Crohn’s in their gut. However, most of those with gut Crohn’s will not develop oral Crohn’s. Common features are facial and lip swelling with soreness and cracking at the corners of the mouth (called angular stomatitis). It can include mouth ulcers, gum swellings (hyperplasia) and redness. Under a microscope, Oral Crohn’s looks exactly like gut Crohn’s.
Crohn’s Disease may involve any segment of the gastrointestinal tract, from the mouth to the anus. In the mouth, nonspecific lesions, including aphthous ulcers, lesions related to poor nutrition, and adverse effects of medication, are common. Specific oral lesions, defined by macroscopic and microscopic changes similar to those observed in the gastrointestinal tract of patients with CD, are uncommon. However, in many studies, no distinction was made between specific and nonspecific oral lesions. Thus, the characteristics of oral CD, especially relative to digestive disease, vary from one study to another.
A list of symptoms is provided on page 3 of this paper. People with severe Crohn’s disease may also experience:
- Inflammation of skin, eyes and joints
- Inflammation of the liver or bile ducts
- Kidney stones
- Iron deficiency (anaemia)
- Delayed growth or sexual development in children
- Obstruction and perforation of the small intestine or colon
- Abscesses (collections of pus)
- Intestinal bleeding
- Kidney stones
Massive distention or dilatation of the colon (megacolon) and rupture (perforation) of the intestine are potentially life-threatening complications. Whilst both may require surgery, fortunately, these two complications are rare. Recent data suggest an increased risk of cancer of the small intestine and colon in patients with long-standing Crohn’s disease, but studies are conflicting.
Other complications can involve the skin, joints, spine, eyes, liver, bones, and bile ducts:
- Skin involvement includes painful, red, and raised spots on the legs (erythema nodosum) and an ulcerating skin condition generally found around the ankles called pyoderma gangrenosum.
- Painful eye conditions (uveitis, episcleritis) can cause visual difficulties.
- Arthritis can cause pain, swelling, and stiffness of the joints of the extremities. Inflammation of the low back (sacroiliac joint arthritis) and the spine (ankylosing spondylitis) can cause pain and stiffness.
- Inflammation of the liver (hepatitis) or bile ducts (primary sclerosing cholangitis) also can occur.
- Sclerosing cholangitis causes narrowing and obstruction of the ducts draining the liver and can lead to yellow skin (jaundice), recurrent bacterial infections, and liver cirrhosis with liver failure. Sclerosing cholangitis with liver failure is one of the reasons for performing a liver transplant. Sclerosing cholangitis often is complicated by the development of cancer of the bile ducts or gallbladder. People who also have cirrhosis are at increased risk of developing liver cancer.
Bowel obstructions, also known as intestinal blockages, occur when intestinal contents are partially or fully blocked and unable to move. There are several ways that this can happen to people with Crohn’s disease:
- Inflammation can thicken the intestinal walls enough to narrow or even close off the intestinal tract. Strictures can cause bowel obstructions. A stricture or stenosis is an area of the gastrointestinal tract that has been narrowed by scar tissue caused by repeated bouts of inflammation. Adhesions, or strips of fibrous tissue that cause organs and tissues to bind together, can block the intestinal tract.
An intestinal blockage can cause severe abdominal pain and often requires hospitalisation to treat. Less severe cases usually resolve with bowel rest (liquid diet), but your doctor may prescribe medication to help prevent future recurrences. More serious cases may require surgery. A surgical procedure called a strictureplasty widens the intestine without removing any part of it.
Fistulas and Abscesses
Ulcers that go completely through the digestive tract wall can create fistulas – these are abnormal connections from the intestines to other body parts. About a third of those with Crohn’s disease will develop a fistula. A fistula in the abdomen could cause food to bypass important bowel areas needed for absorption. Fistulas may also develop from the bowel to the bladder, vagina, or skin, draining the bowel contents into these areas. If left untreated, an infected fistula may form a life-threatening abscess. To prevent serious infection, fistulas should be treated immediately. The treatment options include surgery, medications, or a combination of them.
Due to the chronic inflammation of the intestinal tract and abnormal bowel movements, anal fissures aren’t uncommon in those with Crohn’s disease. An anal fissure is a small tear in the opening of the anus. Among the symptoms of an anal fissure are pain and bleeding during bowel movements. An anal fissure can reach the internal anal sphincter, the muscle that holds the anus closed. If this occurs, the fissure may not be able to heal. If an anal fissure doesn’t heal within about eight weeks, medication or surgery may be required.
Proper nutrition is critical for good health. Your digestive tract is a key site of nutrient absorption. Chronic inflammation in your bowels can interfere with your body’s ability to absorb vitamins and minerals from the foods you eat. Chronic inflammation caused by Crohn’s disease may also suppress your appetite and prevent you from ingesting the nutrients you need to stay healthy. Several significant issues are caused by malnutrition, including anaemia from lack of iron or vitamin B12, common in people with Crohn’s disease. Other problems caused by not getting adequate nutrients include:
- reduced immune system function
- poor healing
- generalised fatigue and pain
- weak muscles and bones
- decreased coordination
- kidney malfunction
- psychological issues like depression
Ulcers (open sores appearing anywhere along the digestive tract) may occur in people with Crohn’s disease. Ulcers can be painful and dangerous if they cause internal bleeding. They can also cause perforations or holes in the intestinal tract, allowing digestive contents to enter the abdomen. If this happens, immediate medical attention is required.
Studies have shown that up to 50% of people with Crohn’s disease develop osteoporosis, which is low bone density. Crohn’s-related issues that contribute to weakened bones include:
- impaired nutrient absorption
- physical discomfort that keeps you from being active
Part of your Crohn’s treatment strategy may be to counteract these issues by taking calcium and vitamin D supplements. You should also consider doing regular weight-bearing exercises. Your doctor will measure and monitor your bone density. This can be done with a painless dual-energy X-ray absorptiometry (DEXA) test.
If you have chronic inflammation of the colon associated with Crohn’s disease, you have a higher risk for colon cancer. The inflammation may result in a constant turnover of the intestinal lining’s cells, increasing the chance of abnormalities and cancer. The following are some of the colon cancer risk factors for people with Crohn’s disease:
- an 8- to 10-year history of the disease
- severe inflammation of the colon
- a family history of colon cancer
- a diagnosis of Crohn’s colitis, a condition that only affects the colon
Colon cancer is very treatable if it is identified in its early stages. Ask your doctor how often you should get a colonoscopy to check for colon cancer.
The prolonged inflammatory response of Crohn’s disease can trigger a similar reaction in joints and tendons, leading to arthritis. The most common type of arthritis for people with Crohn’s disease is peripheral arthritis. In severe cases, arthritis associated with Crohn’s disease may be treated with anti-inflammatory drugs and corticosteroids. Nonsteroidal anti-inflammatory drugs (NSAIDs) aren’t generally recommended because they can irritate the intestinal lining, increasing inflammation.
Between 20% and 50% of people with Crohn’s disease develop small ulcers in their mouths. The most common type is a minor aphthous ulcer, which looks like canker sores and may take about two weeks to heal. Less common is a major aphthous ulcer, and larger sores that can take up to six weeks to heal. In severe cases, your doctor may prescribe immunosuppressive drugs and topical steroids to treat your mouth ulcers.
One of the most common kidney complications associated with Crohn’s disease is kidney stones. They’re more common in people with this disease of the small intestine than in people without it, because fat isn’t being absorbed normally. When fat binds to calcium, a type of salt called oxalate can end up in the kidney, forming stones there. The symptoms of a kidney stone may include pain, nausea and vomiting, and blood in the urine. The usual treatment for a kidney stone is drinking more fluids and eating a low-oxalate diet that includes plenty of juices and vegetables. If a kidney stone doesn’t pass on its own, it may need to be surgically removed.
Other complications associated with Crohn’s disease are eye and skin issues:
Eye pain or itchiness
- About 10% of people with an inflammatory bowel disease like Crohn’s disease experience eye problems such as pain and itchiness.
- Uveitis – a painful inflammation of the eye wall’s middle layer, is one of the most common eye complications. Your ophthalmologist may prescribe eye drops containing steroids to reduce the inflammation.
- Decreased tear production due to a vitamin A deficiency can cause dry eyes that are itchy or burning. Artificial tears can help relieve these symptoms. In severe cases, antibiotics may be prescribed to treat the infection.
Skin sores or rashes
- Skin problems are some of the more common complications of Crohn’s disease. Skin tags may develop around haemorrhoids in the anus. These small flaps form when the skin thickens as the swelling is reduced. Irritation may occur if faecal matter attaches to these skin tags, so keeping the area clean is important.
- Up to 15% of people with Crohn’s disease may have sensitive red bumps (erythema nodosum) on their shins, ankles, or arms.
- Some people may develop lesions (pyoderma gangrenosum) on the same areas of the body. The lesions can be treated with topical ointments or antibiotics.
- Another skin problem associated with Crohn’s disease is Sweet’s syndrome, a rare condition that causes fever and painful lesions on the arms, face, and neck. It is usually treated with corticosteroid medications.
Vitamin B12 and Crohn’s Disease
Someone with Crohn’s disease will experience abdominal pain and unintentional weight loss. They may also have difficulty absorbing certain foods, resulting in nutrient deficiencies. One that commonly occurs is a deficiency of vitamin B12.
Crohn’s disease, a form of inflammatory bowel disease (IBD), is a lifelong condition that results in inflammation and irritation of the digestive tract. Crohn’s disease commonly affects the small intestine and the beginning portion of the large intestine, which is responsible for absorbing nutrients such as vitamin B12.
Vitamin B12 is naturally present in certain foods and is also available as a dietary supplement. It plays an important role in various bodily functions, including developing the central nervous system, red blood cell formation, and DNA synthesis.
Vitamin B12 deficiency is common among people with Crohn’s disease. The disease typically affects the ileum, the last portion of the small intestine, which is where the absorption of vitamin B12 occurs.
Some people with Crohn’s disease may undergo surgical removal of part or all of the ileum, which can also lead to difficulty absorbing vitamin B12.
Warning signs of deficiency
A person with vitamin B-12 deficiency may present with symptoms such as:
- glossitis, which is a swollen and inflamed tongue
- low mood
- lack of energy
- weight loss
- numbness and tingling in the hands and feet
- changes in skin tone, such as pallor in people with light skin and an ashen complexion in people with dark skin
A person with vitamin B12 deficiency may also experience various neurological symptoms, including:
- loss of deep tendon reflexes
- difficulty with concentration
- memory loss
- problems with balance and walking
Anyone experiencing any of the above symptoms should see a doctor. The doctor can rule out other possible causes of the symptoms.
The doctor will usually begin the diagnostic process by asking about the person’s symptoms and medical history and then carrying out a physical exam. They might also conduct a neurological exam if the person is experiencing difficulty concentrating or has any tingling or numbness in their hands or feet.
Healthcare professionals will order laboratory tests to confirm a diagnosis. Initial blood tests may include a complete blood count (CBC) to measure vitamin B-12 and folate levels in the blood. A vitamin B12 level of fewer than 200 picograms per millilitre indicates deficiency. A CBC test will likely show a decrease in haemoglobin and hematocrit in a person with a vitamin B12 deficiency. If your vitamin B12 level remains unclear, a doctor may order additional tests, such as a methylmalonic acid (MMA) blood test. This test measures the blood level of MMA, which the body produces during metabolism. Vitamin B12 has a role in metabolism. Therefore, if the body is deficient in vitamin B12, the level of MMA is likely to increase.
Another type of test is the homocysteine test to measure the level of an amino acid called homocysteine in the blood. Vitamin B12 breaks down homocysteine to produce components that the body uses. A vitamin B12 deficiency will likely result in a higher level of homocysteine in the blood.
Other causes of vitamin B12 deficiency
Other possible causes of a vitamin B12 deficiency include:
- pernicious anaemia
- prolonged use of certain medications, such as metformin
- following a strict vegan or vegetarian diet
- certain infections, such as with the tapeworm Diphyllobothrium latum
- celiac disease
- older age
- high intake of alcohol
Reversing vitamin B12 deficiency
Steps can be taken to prevent or even reverse a vitamin B12 deficiency by supplements, injection, or dietary changes.
According to the US Office of Dietary Supplements, the recommended daily allowance of vitamin B12 for a person over 18 years is 2.4 micrograms (mcg). Vitamin B12 is available in supplements in different doses. These supplements contain either vitamin B12 alone or a combination of B-complex vitamins. Supplements that contain only vitamin B12 tend to have doses in the range of 500–1,000 mcg, whereas supplements that contain multiple B-complex vitamins provide 50–500 mcg of vitamin B12. These supplements do not normally require a prescription, and people can buy them over the counter in supermarkets or pharmacies. Vitamin B12 is also available in tablets and lozenges that people place under the tongue.
If you have a severe vitamin B12 deficiency or difficulty absorbing vitamin B12, you may require an injection of vitamin B12. Some people refer to this as a B12 shot. The injection, which doctors deliver into the muscle, typically contains vitamin B12 in the form of cyanocobalamin or hydroxocobalamin. In a 2019 study, participants with Crohn’s disease reported improvements in their symptoms shortly after receiving a vitamin B12 injection.
Including vitamin B12 in your diet
You can also increase your vitamin B12 intake by following a diet rich in vitamin B12. Foods that are high in vitamin B12 include:
- beef liver
- Seafood – such as clams, tuna, salmon
- fortified breakfast cereals
- dairy – such as milk, yoghurt, cheese
- vegetables – such as lettuce, asparagus, spinach, dark leafy greens
You can learn more about foods that can increase and reduce vitamin B12 levels on the Medical News Today website.
Other supplements for Crohn’s disease
If you have Crohn’s disease, you may also benefit from other nutritional supplements. These may help ensure you get the correct amount of vitamins and nutrients, especially if they are not absorbing enough from food alone. Some supplements that a person may benefit from include:
Help and Advice
The UK’s leading charity for Crohn’s and Colitis is Crohn’s and Colitis UK. The information they provide can help you to understand the disease so you can make informed decisions about your health. There’s also a wealth of information available from the NHS.
Sources and Further Reading
- Video: Professional soccer player Brandi Chastain discusses her son’s diagnosis of Crohn’s Disease at: https://www.britannica.com/video/215082/Crohn-disease-and-Inflammatory-Bowel-Disease
- YouTube Video: Causes, Symptoms & Pathology, at https://youtu.be/thzOJV-CHRo
- YouTube Video: Crohn’s 101, at: https://youtu.be/B8ryJ9P38B8
- YouTube Video: Crohn’s Disease – Surgery, at: https://youtu.be/qkwWaNi3f4s
- Book: How to Cope Successfully with Crohn’s Disease, by Tom Smith (Author), 24th December 2004, available at: https://www.amazon.co.uk/CROHNS-DISEASE-How-Cope-Successfully/dp/1903784166/
- Book: Crohn′s and Colitis For Dummies, 2nd Edition Paperback, for release on 20th December 2022, by Tauseef Ali (Author), available at: https://www.amazon.co.uk/Crohn′s-Colitis-Dummies-2nd-Ali/dp/1119875773/
- Book: Crohn’s Disease and Ulcerative Colitis From Epidemiology and Immunobiology to a Rational Diagnostic and Therapeutic Approach, by Daniel Baumgart, Second edition 10th March 2017, available at: https://blackwells.co.uk/bookshop/product/9783319337012
CAUTION: This paper is not medical advice. No advice is implied or given in articles published by us but is only for general information. You should always seek the advice of your GP or other qualified health provider with any questions you may have regarding a medical condition. This paper is compiled from the sources stated but has not been medically reviewed. It should never be used as a substitute for obtaining advice from a Gastroenterologist or other qualified clinician/medical practitioner. If you have already been given dietary advice, you should not make changes without first talking to your GP, consultant or dietitian. Any medications mentioned may include names for US drugs which may have a different name to those available in the UK. The facts are believed to be correct as at the date of publication, but there may be certain errors and omissions for which we cannot be responsible. There is no implied endorsement or promotion of any organisation by the writer. The hyperlinks were valid at the date of publication.
- Explanation: IBS is a syndrome of exclusion commonly characterised by alternating constipation and diarrhoea. IBS is something that is diagnosed only when other likely diagnoses are ruled out. Source: https://www.sharecare.com/digestive-health/crohns-disease/need-to-know-about-crohns-disease ↑
- Explanation: The ileum is the last and longest section of the small intestine. Here the walls of the small intestine begin to thin and narrow, and blood supply is reduced. Food spends the most time in the ileum, where the most water and nutrients are absorbed. Source: https://my.clevelandclinic.org/health/body/22135-small-intestine ↑
- Source: https://www.sharecare.com/digestive-health/crohns-disease/need-to-know-about-crohns-disease ↑
- See: https://en.wikipedia.org/wiki/Burrill_Bernard_Crohn ↑
- At: https://www.britannica.com/science/Crohn-disease ↑
- Explanation: Johne’s Disease is an infectious wasting condition of cattle and other ruminants caused by Mycobacterium avium subspecies paratuberculosis, commonly known as Map. It is closely related to the organism that causes tuberculosis. ↑
- Mostly excerpted from: https://en.wikipedia.org/wiki/Crohn’s_disease ↑
- Sources: (1) “Crohn’s Disease”. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), (2) Cho JH, Brant SR (May 2011). “Recent insights into the genetics of inflammatory bowel disease”. Gastroenterology. 140 (6): 1704–12, (3) Dessein R, Chamaillard M, Danese S (September 2008). “Innate immunity in Crohn’s disease: the reverse side of the medal”. Journal of Clinical Gastroenterology. 42 (Suppl 3 Pt 1): S144–7. doi:10.1097/MCG.0b013e3181662c90. PMID 18806708, and (4) Stefanelli T, Malesci A, Repici A, Vetrano S, Danese S (May 2008). “New insights into inflammatory bowel disease pathophysiology: paving the way for novel therapeutic targets”. Current Drug Targets. 9 (5): 413–8. ↑
- Sources: (1) Dessein R, Chamaillard M, Danese S (September 2008). “Innate immunity in Crohn’s disease: the reverse side of the medal”. Journal of Clinical Gastroenterology. 42 (Suppl 3 Pt 1): S144–7, and (2) Marks DJ, Rahman FZ, Sewell GW, Segal AW (February 2010). “Crohn’s disease: an immune deficiency state”. Clinical Reviews in Allergy & Immunology. 38 (1): 20–31. ↑
- Source: Casanova JL, Abel L (August 2009). “Revisiting Crohn’s disease as a primary immunodeficiency of macrophages”. The Journal of Experimental Medicine. 206 (9): 1839–43. ↑
- Sources: (1) Marks DJ, Rahman FZ, Sewell GW, Segal AW (February 2010). “Crohn’s disease: an immune deficiency state”. Clinical Reviews in Allergy & Immunology. 38 (1): 20–31, (2) Lalande JD, Behr MA (July 2010). “Mycobacteria in Crohn’s disease: how innate immune deficiency may result in chronic inflammation”. Expert Review of Clinical Immunology. 6 (4): 633–41, and (3) Yamamoto-Furusho JK, Korzenik JR (November 2006). “Crohn’s disease: innate immunodeficiency?”. World Journal of Gastroenterology. 12 (42): 6751–5. ↑
- Source: https://www.sharecare.com/digestive-health/crohns-disease/need-to-know-about-crohns-disease ↑
- See: Baumgart DC, Sandborn WJ (August 2012). “Crohn’s disease”. Lancet. 380 (9853): 1590–605. ↑
- Explanation: Steroids, also called corticosteroids, are anti-inflammatory medicines used to treat a range of conditions. They’re different from anabolic steroids, which are often used illegally by some people to increase their muscle mass. ↑
- Sources: Various, including: https://www.webmd.com/ibd-crohns-disease/crohns-disease/5-types-crohns-disease, https://www.mayoclinicproceedings.org/article/S0025-6196(17)30313-0/pdf, https://www.ibdrelief.com/learn/what-is-ibd/what-is-crohns-disease, and https://www.mayoclinicproceedings.org/article/S0025-6196(17)30313-0/pdf ↑
- Source: https://gut.bmj.com/content/gutjnl/54/1/162.full.pdf ↑
- Source: https://bestpractice.bmj.com/topics/en-gb/42 ↑
- Researchers estimate that more than half a million people in the US have Crohn’s disease. ↑
- Explanation: Resection is the medical term for surgically removing part or all of a tissue, structure, or organ. Source: Kappelman MD, Moore KR, Allen JK, Cook SF. Recent trends in the prevalence of Crohn’s disease and ulcerative colitis in a commercially insured US population. Digestive Diseases and Sciences. 2013;58: 519–525. ↑
- Source: https://www.bmj.com/content/367/bmj.l5940.full ↑
- Source: https://www.mayoclinic.org/diseases-conditions/crohns-disease/symptoms-causes/syc-20353304 ↑
- Source: https://www.cicra.org/what-is-ibd/crohns-disease/oral-crohns/ and https://jamanetwork.com/journals/jamadermatology/fullarticle/477791 ↑
- See: Cleary KRBatsakis JG Orofacial granulomatosis and Crohn’s disease. Ann Otol Rhinol Laryngol. 1996; 105166- 167 ↑
- See: Basu MKAsquith P Oral manifestations of inflammatory bowel disease. Clin Gastroenterol. 1980; 9307- 321 ↑
- Source: https://www.mayoclinic.org/diseases-conditions/crohns-disease/symptoms-causes/syc-20353304 ↑
- Sources: https://www.webmd.com/ibd-crohns-disease/crohns-disease/crohns-disease-complications, https://www.healthline.com/health/crohns-disease/complications-of-crohns ↑
- Explanation: This causes swelling and pain in the large joints of the arms and legs, such as the knees and elbows. Peripheral arthritis usually doesn’t permanently damage the joints. ↑
- Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3870502/ ↑
- Source: https://www.crohnscolitisfoundation.org/emr/emr-ibd-education-tool/eye-complications ↑
- Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4804366/ ↑
- Explanation: Sweet’s Syndrome is an uncommon skin condition marked by a distinctive eruption of tiny bumps that enlarge and are often tender to the touch. They can appear on the back, neck, arms or face. Sweet’s syndrome, also called acute febrile neutrophilic dermatosis, is an uncommon skin condition. Source: https://www.mayoclinic.org/diseases-conditions/sweets-syndrome/symptoms-causes/syc-20351117 ↑
- Source: https://www.medicalnewstoday.com/articles/b12-and-crohns ↑
- Source: https://www.medicalnewstoday.com/articles/vitamin-b12-foods ↑
- See: https://crohnsandcolitis.org.uk/info-support/information-about-crohns-and-colitis/all-information-about-crohns-and-colitis ↑
- At: https://www.nhs.uk/conditions/crohns-disease/, https://www.nhs.uk/conditions/crohns-disease/symptoms/, https://www.nhsinform.scot/illnesses-and-conditions/stomach-liver-and-gastrointestinal-tract/crohns-disease, and https://www.nhs.uk/conditions/crohns-disease/living-with/ ↑