Collagenous colitis is an inflammatory condition of the colon. Together with the related condition lymphocytic colitis, it is a subtype of microscopic colitis, which is characterized by inflammation that specifically affects the colon (i.e.

colitis Colitis is swelling or inflammation Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and ...

), and a clinical presentation that involves watery

diarrhea Diarrhea (American English), also spelled diarrhoea or diarrhœa (British English), is the condition of having at least three loose, liquid, or watery bowel movements in a day. It often lasts for a few days and can result in dehydration d ...

but a lack of rectal bleeding. Microscopic colitis does not usually cause

macroscopic The macroscopic scale is the length scale on which objects or phenomena are large enough to be visible with the naked eye, without magnifying optical instruments. It is the opposite of microscopic. Overview When applied to physical phenome ...

changes to the colon that allow a visual diagnosis during

colonoscopy Colonoscopy () or coloscopy () is a medical procedure involving the Endoscopy, endoscopic examination of the large bowel (colon) and the distal portion of the small bowel. This examination is performed using either a Charge-coupled device, CCD ...

, instead causing

microscopic The microscopic scale () is the scale of objects and events smaller than those that can easily be seen by the naked eye, requiring a lens or microscope to see them clearly. In physics, the microscopic scale is sometimes regarded as the scale betwe ...

changes that can be detected through

histopathological Histopathology (compound of three Greek language, Greek words: 'tissue', 'suffering', and ''-logy, -logia'' 'study of') is the light microscope, microscopic examination of Tissue (biology), tissue in order to study the manifestations of dis ...

examination of colonic biopsies. The nature of these microscopic changes is what differentiates collagenous from lymphocytic colitis, with the characteristic finding in collagenous colitis being depositions of

collagen Collagen () is the main structural protein in the extracellular matrix of the connective tissues of many animals. It is the most abundant protein in mammals, making up 25% to 35% of protein content. Amino acids are bound together to form a trip ...

in the

connective tissue Connective tissue is one of the four primary types of animal tissue, a group of cells that are similar in structure, along with epithelial tissue, muscle tissue, and nervous tissue. It develops mostly from the mesenchyme, derived from the mesod ...

between the colonic glands. Collagenous colitis, and microscopic colitis as a whole, is sometimes considered to be an

inflammatory bowel disease Inflammatory bowel disease (IBD) is a group of inflammatory conditions of the colon and small intestine, with Crohn's disease and ulcerative colitis (UC) being the principal types. Crohn's disease affects the small intestine and large intestine ...

(IBD) along with

Crohn's disease Crohn's disease is a type of inflammatory bowel disease (IBD) that may affect any segment of the gastrointestinal tract. Symptoms often include abdominal pain, diarrhea, fever, abdominal distension, and weight loss. Complications outside of the ...

and

ulcerative colitis Ulcerative colitis (UC) is one of the two types of inflammatory bowel disease (IBD), with the other type being Crohn's disease. It is a long-term condition that results in inflammation and ulcers of the colon and rectum. The primary sympto ...

. However, little is known about the

etiology Etiology (; alternatively spelled aetiology or ætiology) is the study of causation or origination. The word is derived from the Greek word ''()'', meaning "giving a reason for" (). More completely, etiology is the study of the causes, origins ...

of microscopic colitis, and so the degree of similarity to the inflammatory bowel diseases is uncertain. Although cases are known to occur in all age groups, the disease is most frequently diagnosed in late

middle age Middle age (or middle adulthood) is the age range of the years halfway between childhood and old age. The exact range is subject to public debate, but the term is commonly used to denote the age range from 45 to 65 years. Overall This time span ...

d or

elderly Old age is the range of ages for people nearing and surpassing life expectancy. People who are of old age are also referred to as: old people, elderly, elders, senior citizens, seniors or older adults. Old age is not a definite biological sta ...

people, with the average person being diagnosed in their 60s. Women are more frequently affected than men, with different studies finding female-male incidence ratios of between 3 and 8.

Epidemiological Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and Risk factor (epidemiology), determinants of health and disease conditions in a defined population, and application of this knowledge to prevent dise ...

studies have found large increases in diagnosed cases of microscopic colitis, of which collagenous colitis cases are a majority, over the past few decades, with cases of microscopic colitis now outnumbering those of Crohn's disease and ulcerative colitis at least in some regions.

Signs and symptoms

In general, microscopic colitis causes chronic watery diarrhea with increased stool frequency. Some patients report

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

diarrhea,

abdominal pain Abdominal pain, also known as a stomach ache, is a symptom associated with both non-serious and serious medical issues. Since the abdomen contains most of the body's vital organs, it can be an indicator of a wide variety of diseases. Given th ...

, bowel urgency,

fecal incontinence Fecal incontinence (FI), or in some forms, encopresis, is a lack of control over defecation, leading to involuntary loss of bowel contents—including flatus (gas), liquid stool elements and mucus, or solid feces. FI is a sign or a symptom ...

fatigue Fatigue is a state of tiredness (which is not sleepiness), exhaustion or loss of energy. It is a signs and symptoms, symptom of any of various diseases; it is not a disease in itself. Fatigue (in the medical sense) is sometimes associated wit ...

and weight loss. In severe cases, symptoms may include

dehydration In physiology, dehydration is a lack of total body water that disrupts metabolic processes. It occurs when free water loss exceeds intake, often resulting from excessive sweating, health conditions, or inadequate consumption of water. Mild deh ...

and electrolyte imbalances. Patients report a significantly diminished quality of life. In a retrospective study specifically on collagenous colitis patients, all studied patients experienced chronic diarrhea, 42% experienced weight loss, 41% experienced abdominal pain, 27% of the patients experienced

diarrhea, while 14% experienced fatigue and 8% experienced meteorism. The median patient had 6 stools per day. Among the patients who experienced weight loss and whose magnitude of weight loss was recorded, the median lost weight was 6 kg.

Causes

The cause of collagenous colitis is unknown. A connection with autoimmune disorders such as

celiac disease Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine. Patients develop intolerance to gluten, which is present in foods such as wheat, rye, spel ...

is suspected, as up to 40% of patients with collagenous colitis have an autoimmune disease. Use of

nonsteroidal anti-inflammatory drugs A nonsteroidal compound is a drug that is not a steroid nor a steroid derivative. Nonsteroidal anti-inflammatory drugs (NSAIDs) are distinguished from corticosteroids as a class of anti-inflammatory agents. List of nonsteroidal steroid receptor mod ...

(NSAIDs),

proton pump inhibitors Proton-pump inhibitors (PPIs) are a class of medications that cause a profound and prolonged reduction of gastric acid, stomach acid production. They do so by irreversibly inhibiting the stomach's H+/K+ ATPase, H+/K+ ATPase proton pump. The body ...

(PPIs) and

beta blockers Beta blockers, also spelled β-blockers, are a class of medications that are predominantly used to manage abnormal heart rhythms (arrhythmia), and to protect the heart from a second heart attack after a first heart attack (secondary prevention). ...

also appear to increase the risk of collagenous colitis, but the cause of this is not known.

Diagnosis

, the

mucosa A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It ...

of the colon typically looks normal, but biopsies of affected tissue usually show deposition of

in the

lamina propria The lamina propria is a thin layer of connective tissue that forms part of the moist linings known as mucous membranes or mucosae, which line various tubes in the body, such as the respiratory tract, the gastrointestinal tract, and the urogenital ...

, which is the area of

between colonic glands. Radiological tests, such as a barium enema are also typically normal.

Treatment

First line treatment for collagenous colitis is the use of budesonide, a steroid that works locally in the colon and is highly cleared by

first pass effect The first pass effect (also known as first-pass metabolism or presystemic metabolism) is a phenomenon of drug metabolism at a specific location in the body which leads to a reduction in the concentration of the active drug before it reaches the ...

. Other medications that can be used include the following: *

Bismuth Bismuth is a chemical element; it has symbol Bi and atomic number 83. It is a post-transition metal and one of the pnictogens, with chemical properties resembling its lighter group 15 siblings arsenic and antimony. Elemental bismuth occurs nat ...

agents, including Pepto-Bismol * 5-aminosalicylic acid *

Immunosuppressants Immunosuppressive drugs, also known as immunosuppressive agents, immunosuppressants and antirejection medications, are drugs that inhibit or prevent the activity of the immune system. Classification Immunosuppressive drugs can be classified ...

, including azathioprine *

Infliximab Infliximab, a chimeric monoclonal antibody, sold under the brand name Remicade among others, is a medication used to treat a number of autoimmune diseases. This includes Crohn's disease, ulcerative colitis, rheumatoid arthritis, ankylosing ...

Pilot-scale studies have shown some evidence of possible benefit for both '' Boswellia serrata'' extract and specific strains of

probiotics Probiotics are live microorganisms that provide health benefits when consumed, generally by improving or restoring the microbiota in the Gut microbiota, gut. Probiotics are considered GRAS, generally safe to consume, but may cause bacteria– ...

in the treatment of collagenous colitis, although larger sample sizes are needed to confirm the results.

Epidemiology

One epidemiological study reported previous

incidence rate In epidemiology Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and Risk factor (epidemiology), determinants of health and disease conditions in a defined population, and application of this knowl ...

s of collagenous colitis found in the literature as ranging from 0.6 cases per 100,000 person-years (based on French data from 1987–1992) to 5.2 per 100,000 person-years (from an Icelandic study based on data from 1995–1999), while the authors themselves found an incidence rate of 3.1 per 100,000 person-years in Olmsted County, Minnesota across the period 1985–2001. Based only on the subset of the data from 1998–2001, however, the authors found a higher rate of 7.1 per 100,000 person-years, an incidence rate which exceeded those of Crohn's disease and ulcerative colitis. The previously mentioned Icelandic study also found increasing rates through the studied period, with the incidence rate in Iceland increasing from 2.2 in 1995 to 8.3 in 1999. Women appear to be more frequently affected by collagenous colitis than men, with the Icelandic study finding a female–male ratio of 7.9 in diagnosed cases and the Olmsted County study finding a female–male ratio of 4.4. An updated study on microscopic colitis in Olmsted County published in 2022 and based on data from between 2011 and 2019 found an incidence rate for collagenous colitis of 9.9 cases per 100,000 person-years, a

prevalence In epidemiology, prevalence is the proportion of a particular population found to be affected by a medical condition (typically a disease or a risk factor such as smoking or seatbelt use) at a specific time. It is derived by comparing the number o ...

of 100.1 per 100,000 persons and a female–male ratio of 4.7. Unlike in the previous study on data from 1995–1999, the rate of collagenous colitis in Olmsted County was found to have remained stable between 2011 and 2019. Another study on rates of microscopic colitis in

Denmark Denmark is a Nordic countries, Nordic country in Northern Europe. It is the metropole and most populous constituent of the Kingdom of Denmark,, . also known as the Danish Realm, a constitutionally unitary state that includes the Autonomous a ...

between 2001 and 2016 found an overall incidence rate for collagenous colitis of 12.2 per 100,000 person-years, a prevalence of 116.7 per 100,000 persons and a female–male ratio of 3.1. Like the 1995–1999 Olmsted County study and the 1995–1999 Icelandic study, this Danish study found a heavy increase in rates of collagenous colitis and microscopic colitis overall during the studied period, with the incidence rates in 2001 and 2016 for microscopic colitis found to be, respectively, 2.3 and 24.3 cases per 100,000 person-years. However, the incidence rates of collagenous colitis in this Danish data peaked in 2011 with a rate of 19.6 cases per 100,000 person-years, and rates appeared to be stable between 2012 and 2016. The average age at diagnosis was found to be 67, and the highest incidence rate was found among patients over the age of 80. The strong increase in the case rates of microscopic colitis (with collagenous colitis making up 59% of these cases) throughout the study period meant that by 2016, microscopic colitis had a greater incidence rate in Denmark than did Crohn's disease and ulcerative colitis. The authors suggest an increase in the use of colonoscopies as a possible cause of the observed change in microscopic colitis diagnoses over time.

References

External links

{{Authority control Colitis Steroid-responsive inflammatory conditions