IBS and IBD are two separate conditions that affect the bowel, with some essential similarities and differences. IBD includes a pair of structural autoimmune diseases: ulcerative colitis and crohn's disease, both of which cause inflammation and damage within the bowel. They may require surgical intervention and hospital stays in severe examples of the condition. Irritable bowl syndrome (IBS) is a functional disease, or syndrome, and is related to gut motility (the speed at which food passes through the digestive system) and very rarely requires hospitalization.
We’ve spoken to some medical and gut health experts about the main similarities and differences between IBD vs IBS, including symptoms, diagnostic processes, treatments and pain. If you suspect you may be suffering from either, it’s important to consult your doctor so they can carry out appropriate diagnostic tests.
IBD vs IBS: Overview
IBD and IBS are both gastrointestinal conditions that can cause stomach pain, bathroom issues and nausea, with the potential to cause significant disruption to your day-to-day life. However, IBD is a structural disease, rather than a syndrome, which causes permanent damage to the digestive system through inflammation and increases a patients’ risk of developing colon cancer.
There are visible signs of IBD in the bowel that can be seen when doctors perform a colonoscopy (which is how IBD is generally diagnosed). IBS, on the other hand, has no visible signs of damage, is not inflammatory and does not increase the risk of bowel cancer in those who have it. According to a review in Clinics in Colorectal Surgery, the latter is a particular risk for IBD patients.
“IBS is a functional condition affecting the gastrointestinal tract which gives rise to a wide range of unpleasant symptoms such as abdominal pain, bloating, passing wind, diarrhea and constipation,” explains Dr Deborah Lee, MD. “The exact cause of the condition is not well understood, but there is miscommunication in the gut-brain axis. The bowel becomes hypersensitive to certain foods.
Having worked for many years in the NHS, initially as a GP, and then as Lead Clinician for an integrated Community Sexual Health Service, Dr Deborah Lee now works as a health and medical writer, with an emphasis on women’s health. She is a menopause specialist.
"IBD is the term used to describe two specific medical conditions which affect the gut – crohn’s disease and ulcerative colitis. The symptoms are similar to IBS with abdominal pain, bloating, and diarrhea. However, in both these conditions, the gut becomes inflamed, and this can be severe. The inflammation causes damage to the bowel wall, with the long-term risk of strictures (scar tissue in the bowel wall) and/or bowel perforations, which are life-threatening and can be fatal.”
IBD vs IBS: Symptoms
IBD and IBS are similar in some ways. Both conditions cause abdominal pain, bloating, mucousy stools and diarrhea, however rectal bleeding, anemia and unexplained weight loss are all signs of IBD only. As IBD is an autoimmune condition it can also cause swelling of the joints, eyes and skin and sometimes alopecia.
Although we aren’t entirely sure why hair loss is associated with IBD, a study in the Word Journal of Gastroenterology found it to be a common symptom. IBD can also trigger secondary autoimmune conditions in those who have it, according to another World Journal of Gastroenterology study.
Those with IBS will often have a feeling of bathroom urgency, but this tends to change or go away after a bowel movement. With IBD, patients often experience fecal incontinence according to a study in the Journal of Crohns and Colitis, which has been shown to significantly impact quality of life. Around 24% of those with IBD were thought to be affected overall, although 74% of respondents in this particular study reported experiencing fecal incontinence. Although those with IBS also experience fecal incontinence, it is generally only in severe cases, with 14-20% reporting this symptom in a Neurogastroenterology & Motility Journal study.
“There are different types of IBS, and the symptoms someone experiences tell us a lot about the type of IBS they may have,” says Caitlin Hall, a registered dietician and head of clinical research at Myota.
Caitlin Hall is an Accredited Practising Dietitian (APD) and the Head of Clinical research at Myota. She holds a PhD in neurosciences and gut microbiology. Her research combines functional neuroimaging and microbiome sequencing to understand how the gut microbiome influences human brain network dynamics supporting anxiety. She is passionate about the translation of gut-brain axis research from preclinical models to human studies, and exploring the potential for future applications in clinical settings and general health.
“IBS-C refers to where constipation is prevalent and IBS-D refers to diarrhea as the main symptom and with IBS-B (or IBS-M), it's a combination of both. Regardless of type, it is still important to rule out other conditions such as coeliac disease and inflammatory bowel disease as many of the symptoms overlap.”
IBD vs IBS: Pain
Pain is a symptom that characterizes both IBS and IBD, and can be debilitating with both conditions.
“Both conditions cause cramping and lower abdominal pain,” says Dr. Lee. “However, IBD tends to cause pain lower down on the left side of the abdomen, whereas IBS causes generalized discomfort across the whole area.
“The pain of IBD is often more severe and has been described as a knife twisting in the gut or sometimes compared to labor pains. It may make the patient bend forwards holding their stomach in agony. IBS sufferers too often experience severe pain, using words to describe it such as unbearable, indescribable, excruciating, and intense.”
IBD vs IBS: Treatment
IBS and IBD need different treatment plans due to the ways they affect the body. IBS treatments tend to be based around the management of symptoms, as there is no physical damage occurring, so lifestyle changes such as a low-FODMAP diet may be recommended.
IBD treatments can be pharmacological or sometimes surgical, if the disease is severe. In the most severe cases, an ostomy may be considered, bypassing the bowel either temporarily or permanently. This may be a planned procedure or may be carried out under emergency circumstances if a patient is in a flare.
Both IBS and IBD patients can benefit from therapies to help handle stress and anxiety, as both conditions are often related to poor mental health. Abnormal anxiety levels are found in up to 40% of IBD patients, according to a study in Clinical and Experimental Gastroenterology. Another study in the European Archives of Psychiatry and Clinical Neuroscience found that, in comparison to healthy control subjects, patients with IBS showed significantly higher levels of anxiety and depression.
“Treatment for IBD may include medications like aminosalicylates (5-ASAs), corticosteroids, immunomodulators, and biologics,” says Hall. “The way IBD is managed is very individual and treatment may also need to change over the course of time; some people may also eventually require surgery, including gut resections, colectomy, colostomy. The role of diet – particularly the Mediterranean diet – is now also recognized as playing a key role in effectively managing IBD. Dietary recommendations should emphasize high fiber – including prebiotics – healthy fats, and fruit and vegetable diversity”
Hall also says that around 30% of individuals with IBD also have concurrent IBS. For example, when people with IBD are in a period of remission (when symptoms reduce or disappear, often temporarily), they will continue to experience hypersensitivity in the gut such as pain and altered bowel function, in the absence of inflammation.
This article is for informational purposes only and is not meant to offer medical advice.
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Lou Mudge is a health writer based in Bath, United Kingdom for Future PLC. She holds an undergraduate degree in creative writing from Bath Spa University, and her work has appeared in Live Science, Tom's Guide, Fit & Well, Coach, T3, and Tech Radar, among others. She regularly writes about health and fitness-related topics such as air quality, gut health, diet and nutrition and the impacts these things have on our lives.
She has worked for the University of Bath on a chemistry research project and produced a short book in collaboration with the department of education at Bath Spa University.