Bleeding from the anus: causes in men and women, treatment

Rectal bleeding is a symptom, not a diagnosis. It refers to the appearance of blood from the anal canal, rectum, or colon, and can be either harmless (for example, with grade I-II internal hemorrhoids) or serious (for example, with diverticular bleeding or ischemic colitis). Color, volume, and accompanying signs help narrow the cause, but a definitive answer is usually provided by examination, endoscopy, and, if necessary, imaging. Guidelines emphasize that it is not always safe to attribute bleeding to hemorrhoids without an examination. [1]

Blood may be bright red on paper or in the toilet (hematochezia) or dark, sometimes in clots. Excessive hematochezia most often indicates a source in the colon, but with very rapid upper gastrointestinal bleeding, bright red blood may also appear from the anus. Therefore, the evaluation begins with checking vital signs, the volume of blood loss, and risk factors (anticoagulants, nonsteroidal anti-inflammatory drugs). [2]

Current management is based on major guidelines from the American College of Gastroenterology and the British Society of Gastroenterology. These guidelines describe risk assessments, transfusion strategies, when to use computed tomography angiography and when to use colonoscopy, and when to include interventional radiology. This has helped reduce mortality and the number of unnecessary emergency colonoscopies. [3]

It's important to be aware of the "red flags": falling blood pressure, rapid pulse, dizziness, severe weakness, black stools, red blood with clots, anemia, weight loss, age over 50 without a recent colonoscopy, and a family history of cancer. If these are present, an urgent in-person evaluation is needed and, as a rule, hospitalization for stabilization and diagnostic clarification. [4]

Code according to ICD-10 and ICD-11

In the International Classification of Diseases, 10th revision, bleeding from the anus and rectum is coded as K62.5 ("Hemorrhage of anus and rectum"). This code is used when the source of bleeding is specified as anorectal, but the primary disease has not yet been established or is described separately. If a specific cause is identified, the codes for the underlying disease are used: hemorrhoids (I84 / in modifications - block K64), anal fissure (K60), diverticular disease with bleeding (K57 with the specification "with bleeding"), colorectal neoplasms, etc. [5]

ICD-11 includes the ME24.A1 category ("Haemorrhage of anus and rectum") in the gastrointestinal tract. Additional post-coordination options are available: ME24.A3 ("Haematochezia"), ME24.9Z ("Gastrointestinal bleeding, unspecified"), and cross-references "code elsewhere" if the bleeding is due to a specific disease (e.g., hemorrhoids DB60.* or tumor). This allows for a more accurate description of the episode and its cause in the medical documentation. [6]

Table 1. ICD codes for rectal bleeding

System	Code	Name / when used
ICD-10 (WHO, basic)	K62.5	Bleeding from the anus and rectum (primary symptom, cause unknown)
ICD-10 (examples of causes)	I84 / K64, K60, K57.*	Hemorrhoids; anal fissure; diverticulosis/diverticulitis with bleeding
ICD-11 MMS	ME24.A1	Bleeding from the anus and anal canal (rule out causes coded elsewhere)
ICD-11 MMS (related)	ME24.A3; ME24.9Z	Hematochezia; unspecified gastrointestinal bleeding
ICD-11 MMS (examples of causes)	DB60 , 2B80, DA**	Hemorrhoids; colon neoplasms; inflammatory colitis (code separately)
Based on ICD-10 and ICD-11 navigators. [7]

Epidemiology

According to primary care data, approximately 10% of adults report rectal bleeding per year; up to 20% of family physician patients recall an episode in the previous 12 months. Most cases are mild and self-limited, but in some patients, bleeding recurrs or masks a serious pathology. [8]

Hospitalizations for acute lower gastrointestinal bleeding account for approximately 20-87 cases per 100,000 people per year in developed countries; the proportion of all gastrointestinal bleeding is approximately 20-33%. These rates depend on age, anticoagulant use, and comorbidities. [9]

Large national data show an increasing proportion of lower-grade hemorrhages in hospitalizations over recent decades, amid an aging population and the widespread use of antiplatelet and anticoagulant medications. While mortality from lower-grade hemorrhages is lower than from upper-grade hemorrhages, the risk of anemia and recurrent episodes remains. [10]

The most common causes of hospitalization with acute lower bleeding in Western countries are diverticular bleeding and anatomical vascular abnormalities (angiodysplasia); outpatient minor bleeding is more often associated with hemorrhoids and anal fissure.[11]

Reasons

Causes of anorectal and lower intestinal bleeding include hemorrhoids (especially internal), anal fissures, diverticular bleeding, angiodysplasia, inflammatory bowel disease (ulcerative colitis, Crohn's disease), ischemic colitis, infectious colitis, radiation proctitis, polyps and colorectal cancer, as well as procedural consequences and drug-induced injuries (e.g., due to nonsteroidal anti-inflammatory drugs). Sometimes scarlet blood occurs with very rapid upper bleeding (e.g., ulcers), which requires differentiation. [12]

Hemorrhoids and fissures are more common in young people, while diverticular bleeding and angiodysplasia are more common in older people. Chronic constipation and prolonged sitting on the toilet increase the risk of anorectal causes, while atherosclerosis and circulatory disorders increase the risk of ischemic colitis. Severe episodes requiring transfusions are more often associated with diverticular and vascular sources. [13]

Malignant neoplasms of the colon and rectum often cause occult blood loss and iron deficiency anemia, but may also present with visible blood, especially if located in the left colon. Any unexplained bleeding in people over 50 years of age is a reason for a colonoscopy if indicated. [14]

Finally, anticoagulants and antiplatelet agents do not "create" a source, but rather increase any bleeding. The recommendations emphasize the rules for their temporary discontinuation, correction, and resumption, as well as the use of reversible agents in the event of life-threatening bleeding. [15]

Table 2. Common causes and guidelines

Cause	A typical picture	Comments
Haemorrhoids	Scarlet blood on paper/in the toilet, little pain	Common outpatient cause; examination/anoscopy required. [16]
Anal fissure	Sharp pain like a blade + scarlet blood	Visible rupture of skin/mucous membrane. [17]
Diverticulosis (bleeding)	Sudden scarlet blood, sometimes profusely	Leader in hospitalizations for lower back bleeding. [18]
Angiodysplasia	Recurrent episodes in the elderly	Endoscopic coagulation is often required.[19]
Ischemic/inflammatory colitis	Abdominal pain, bloody diarrhea	Require colonoscopy and etiotropic treatment. [20]

Risk factors

Non-modifiable factors include age (over 60 years increases the risk of diverticular and vascular causes), male gender in some cohorts, and a family history of cancer. These factors alter the threshold of suspicion, particularly during the first episode of bleeding. [21]

Modifiable factors include chronic constipation and prolonged sitting on the toilet, physical inactivity, obesity, diets deficient in fiber and water, abuse of nonsteroidal anti-inflammatory drugs, smoking (through coughing and tissue effects), and heavy lifting with breath holding. These habits increase the mechanical load on the anorectal structures. [22]

High-risk medications include anticoagulants and antiplatelet agents, nonsteroidal anti-inflammatory drugs, and, less commonly, glucocorticoids and mucosal irritants. When prescribing these medications, it is important to develop a preventive and monitoring plan, especially in elderly patients with comorbidities. [23]

Special risk groups include pregnant women (due to constipation and hemorrhoids), patients after pelvic radiation therapy (radiation proctitis), and people with cirrhosis and portal hypertension: they may have rectal varices, which superficially resemble hemorrhoids but require a different approach. [24]

Pathogenesis

In anorectal causes, mechanical factors play a leading role: straining, prolonged sitting, repeated "bursts" of intra-abdominal pressure (coughing, heavy exercise). These factors overload the anal cushions and the mucocutaneous junction, leading to microtrauma, bleeding, and prolapse. [25]

Diverticular bleeding is most often associated with rupture of a feeding vessel at the neck of the diverticulum. Bleeding can be intense but tends to stop spontaneously; recurrences require endoscopic or radioendovascular interventions. [26]

Angiodysplasias are dilated, superficially located vascular lesions of the mucosa and submucosa. Their walls are thinned, leading to intermittent bleeding, especially in the presence of anticoagulants. Thermocoagulation and argon plasma coagulation are effective. [27]

Ischemic colitis occurs with a transient decrease in perfusion: spasm, pain, and then bleeding are typical. Inflammatory and infectious colitis damage the mucosa through immune and toxic mechanisms and often produce blood along with diarrhea and pain. These variants require etiotropic therapy in addition to hemostasis. [28]

Symptoms

Scarlet blood on paper, drops in the toilet bowl, streaks in the stool—these are classic signs of an anorectal source. With internal nodes of grades I-II, pain is minimal; with a fissure, the pain is sharp, "cutting," during and after defecation. Itching, skin irritation, and a feeling of "incomplete emptying" are often noted. [29]

A large volume of bright red blood with clots without significant pain most often indicates diverticular bleeding or a vascular anomaly. Such episodes can cause dizziness, a drop in blood pressure, and require urgent evaluation and intravenous therapy. [30]

Blood with diarrhea and abdominal pain suggests colitis (inflammatory, infectious, ischemic). Black, tarry stools are more typical of upper sources, but with very rapid upper bleeding, scarlet blood from the rectum may occur. [31]

Chronic bleeding and iron deficiency anemia without obvious acute episodes are a reason to look for polyps or cancer, especially in people over 50 years of age or with a family history. [32]

Classification, forms and stages

Depending on the location, bleeding is classified as anorectal (anal canal, rectum) and distal colonic (sigmoid, descending, transverse colon and above to the ileocecal angle). This helps determine the diagnostic method: anoscopy and rectoscopy versus full colonoscopy or computed tomography angiography. [33]

By severity - mild (traces on paper), moderate (visible scarlet blood without signs of hypovolemia) and severe (hemodynamic instability, drop in hemoglobin, need for transfusions). Severity determines the route: outpatient, inpatient, resuscitation. [34]

Based on the course of the disease, it is classified as acute (up to 3 days), protracted (lasting more than 3 days but less than 3 months), and chronic (recurring episodes). This influences the choice of imaging method and the window for colonoscopy. [35]

By origin - mechanical/anatomical (hemorrhoids, fissure, diverticulum, angiodysplasia), inflammatory/ischemic, neoplastic, iatrogenic/medicinal. This grouping is convenient for stratification and selection of therapy. [36]

Table 3. Classification of rectal bleeding (simplified)

Axis	Categories	Why do you need to know this?
Localization	Anorectal/colonic	Selection of examination and endoscopy tactics
Heaviness	Mild / Moderate / Severe	Patient route and transfusion strategy
Flow	Acute / protracted / chronic	Selecting the time and method of examination
Etiology	Mechanical, inflammatory, vascular, neoplastic, medicinal	Targeted treatment
Based on current clinical guidelines.[37]

Complications and consequences

The main risks are iron deficiency anemia, hypovolemia, and the need for transfusions and interventions. In elderly patients with comorbidities, even moderate blood loss worsens outcomes and increases the risk of hospitalization and recurrent episodes. [38]

Recurrences are possible with diverticular and vascular sources, sometimes requiring repeat endoscopic or X-ray endovascular procedures. Without eliminating the triggering medications (nonsteroidal anti-inflammatory drugs, antiplatelet agents for primary prevention), the risk of recurrent bleeding is higher. [39]

Delayed diagnosis risks missing significant illnesses, from inflammatory colitis to cancer. This is especially critical in patients over 50 years of age with bleeding, as well as with associated weight loss and changes in bowel habits. [40]

Finally, self-medication with suppositories for an unidentified source sometimes masks symptoms and delays needed endoscopy. With recurring episodes, it's important to follow a treatment plan rather than rely solely on empirical topical remedies. [41]

When to see a doctor

Immediately - if there are signs of severe bleeding: dizziness, weakness, fainting, stool with large amounts of scarlet blood or clots, a drop in blood pressure, or a rapid pulse. This is a reason to call an ambulance and hospitalize. [42]

In the coming days - if you have recurring or unexplained bleeding, especially if you are over 50 years old and have not had a recent colonoscopy, if there is a family history of colorectal cancer, if you have anemia, weight loss, or a change in the frequency and shape of your stool. [43]

If you experience razor-sharp pain and bright red blood, characteristic of a fissure, an examination is also essential: a doctor will confirm the diagnosis and prescribe treatment to prevent chronicity. If hemorrhoids are the culprit, it's important to assess the severity and rule out other "mimicking" conditions (polyps, proctitis, rectal varices due to portal hypertension). [44]

After an episode associated with anticoagulants, antiplatelet agents, or nonsteroidal anti-inflammatory drugs, a review of the regimen with the treating physician is necessary to reduce the risk of recurrence. [45]

Diagnostics

Step 1. Stability assessment. Blood pressure, pulse, and oxygen saturation are checked, and the volume of blood loss is estimated. If instability is present, venous access, fluids, laboratory testing, and preparation for transfusion using a restrictive strategy are considered (the hemoglobin threshold is usually around 7 g/dL, higher in patients with severe ischemia). [46]

Step 2. History and physical examination. Blood color and volume, pain, diarrhea or constipation, medications (anticoagulants/antiplatelet agents, nonsteroidal anti-inflammatory drugs), recent procedures, pregnancy. Physical examination, digital examination, anoscopy if an anorectal source is suspected. [47]

Step 3. Laboratory. Complete blood count (hemoglobin, platelets), coagulogram, biochemistry (urea/creatinine), blood type and Rh factor, ferritin in case of chronic blood loss. These data guide transfusion tactics and the speed of action. [48]

Step 4. Imaging in severe cases. In cases of ongoing hemodynamically significant bleeding, computed tomography angiography (CTA) is recommended as the first-line imaging modality to precisely localize the source. If CTA is positive, promptly call an interventional radiologist for embolization; in experienced centers, targeted colonoscopy may be possible. [49]

Step 5. Endoscopy. For hospitalized patients with lower bleeding, a planned in-hospital colonoscopy after preparation is recommended rather than an emergency one, as performing an "urgent colonoscopy within the first 24 hours" has not been shown to be beneficial in terms of mortality or recurrence. If bleeding subsides and a recent high-quality colonoscopy is performed, observation is sometimes chosen. [50]

Table 4. Diagnostic tools: when to choose what

Method	When is the best time?	Strengths	Restrictions
Anoscopy	Suspected anorectal source	Fast, cheap, at your bedside	Cannot see proximal to the rectum
CTA	Acute, ongoing severe bleeding	Localizes the source, quickly directs to embolization	Less useful if bleeding is minor/stopped
Colonoscopy	After stabilization/preparation	Diagnostics and one-stage hemostasis	Preparation, time, and resources are needed.
Radioisotope scanning	Slow, intermittent bleeding	Sensitive to low speeds	Less accessible, low localization accuracy
Based on ACG and BSG recommendations.[51]

Differential diagnosis

Hemorrhoids vs. fissures. Hemorrhoids typically produce painless, bright red blood on paper or in the toilet; fissures cause sharp pain and drops of blood, and a visible "tear" in the skin/mucous membrane. Treatment and self-care methods vary, so a basic examination is essential. [52]

Diverticular bleeding vs. colitis. A diverticulum often produces a "fountain" of bright red blood without pain; colitis is accompanied by diarrhea and abdominal pain. In the former case, the key is endoscopic/radioendovascular hemostasis; in the latter, etiotropic therapy and support are essential. [53]

An anorectal source vs. the "mask" of upper bleeding. With very rapid upper bleeding, scarlet blood may appear from the anus, but it is often accompanied by nausea, previously black stools, and elevated urea. Clinical evaluation, probing, and the priority of upper endoscopy are helpful here. [54]

Hemorrhoids vs. rectal varices. With portal hypertension, the submucosal veins dilate—these are not hemorrhoidal sacs. They look similar, but the tactics and risks are different, so patients with liver disease should not be diagnosed with hemorrhoids without endoscopy. [55]

Treatment

The first principle is stabilization. If significant blood loss is detected, venous access, crystalloids, oxygen as indicated, and blood transfusion are established. A restrictive transfusion strategy is recommended: red blood cells are typically transfused at a hemoglobin level of approximately 7 g/dL (higher values are indicated in cases of myocardial ischemia and other special situations). Concurrently, coagulopathy is corrected and a gastroenterologist/proctologist is consulted. [56]

The second principle is to stop active bleeding in severe cases. If hematochezia continues and there is hemodynamic instability, CTA is the first step to localizing the source. If extravasation is detected, the patient is immediately referred for transcatheter arteriography with embolization; in experienced centers, targeted colonoscopy after a positive CTA is also acceptable. This reduces the time to hemostasis. [57]

The third principle is endo-hemostasis during colonoscopy. After bowel preparation, the endoscopist uses clipping, epinephrine injection, thermocoagulation, or argon plasma coagulation, depending on the cause (diverticulum, angiodysplasia, colitis with bleeding areas). For many angiodysplasias, thermal methods are often chosen based on the area. [58]

Not everyone requires an "urgent colonoscopy <24 hours." Updated guidelines show that nonemergent colonoscopy after stabilization and preparation has comparable outcomes in terms of recurrence and mortality, and is sometimes safer for the patient and the team. The exception is ongoing bleeding, when early targeted endoscopy is necessary. [59]

Hemorrhoids and fissures are treated with targeted therapy. For hemorrhoids, the basic treatment is 25-35 g of fiber per day, water, limited time spent in the toilet, and short-term topical treatments. For persistent symptoms, in-office techniques are used (ligation with latex rings, infrared coagulation, sclerotherapy). For fissures, stool softening and local vasodilators are used; in chronic cases, botulinum therapy or sphincterotomy are considered. [60]

Medication management. In case of diverticular bleeding, nonsteroidal anti-inflammatory drugs (NSAIDs) are recommended to be discontinued; aspirin use is decided on an individual basis: for primary prevention, it is usually discontinued; for secondary prevention, it is balanced against risks and reintroduced as indicated. Anticoagulants and antiplatelet agents are adjusted according to regimens, with the use of reversible agents in case of life-threatening bleeding. [61]

Interventional radiology. When endoscopy is impossible or unsuccessful, embolization of the affected arterial branch offers a high chance of hemostasis and avoids surgery. Modern protocols favor embolization after a positive CTA; repeat sessions are possible in case of recurrence. [62]

Surgery as a reserve. Surgery is indicated for ongoing massive bleeding resistant to endoscopy and embolization, as well as complications (perforation, necrosis), or tumors. The extent of the intervention depends on the location of the source and the patient's general condition. [63]

Treatment of causative colitis. For infectious colitis, etiotropic drugs are used; for inflammatory colitis, anti-inflammatory therapy under the supervision of a gastroenterologist; for ischemic colitis, perfusion support and caution with vasoconstrictors. Monitoring for complications is necessary, especially in the elderly. [64]

Prevention of anemia and relapse. After an episode has resolved, follow-up examinations (if there has been no recent high-quality colonoscopy), iron supplementation (orally or intravenously as indicated), and adjustments to medications and risk factors (diet, water, toilet habits) are important. The goal is to restore quality of life and reduce the likelihood of recurrence. [65]

Table 5. Treatment methods and their roles

Direction	When to apply	What does it give?
Stabilization and transfusions	Any significant bleeding	Safe "window" for diagnosis/treatment; Hb threshold usually ~7 g/dL
CTA → embolization	Heavy ongoing bleeding	Rapid localization and hemostasis without surgery
Colonoscopy with hemostasis	After preparation/stabilization	Clips, injection, coagulation, diagnosis of causes
Targeted treatment of anorectal causes	Hemorrhoids, fissure	Symptom control and relapse prevention
Drug correction	NSAIDs/anticoagulants/antiplatelet agents	Reducing the risk of rebleeding
Surgery	Refractory bleeding/tumors	Radical elimination of the source
Based on ACG and BSG recommendations. [66]

Prevention

The foundation is soft, formed stools without straining: 25-35 g of fiber daily, adequate water, activity, limiting toilet time to a few minutes, and avoiding smartphone use. These steps reduce the risk of anorectal bleeding and improve outcomes for hemorrhoids and fissures. [67]

Medication hygiene: If possible, avoid long courses of nonsteroidal anti-inflammatory drugs without appropriate medical indications; consider the need for aspirin for primary prevention; and monitor anticoagulant use. Discuss any changes with your physician. [68]

Age- and risk-based colorectal cancer screening reduces the likelihood of missing a significant source of chronic blood loss. After an episode of unexplained rectal bleeding in people over 50 years of age, targeted endoscopic evaluation is indicated. [69]

Cough control and lifting technique reduce peak intra-abdominal pressures and mechanical stress on the anorectal area, especially in people with pre-existing nodules and fissures.[70]

Forecast

Most mild anorectal bleeding is self-limiting and responds well to lifestyle modifications and minimally invasive procedures. The risk of recurrence is higher in cases of persistent triggers (constipation, prolonged sitting, nonsteroidal anti-inflammatory drugs), as well as in the elderly and patients on anticoagulants. [71]

Diverticular bleeding may result in repeated episodes; modern endoscopy and embolization provide effective control without surgery in most cases. Mortality rates for lower bleeding are lower than for upper bleeding, but age and comorbidity influence outcome. [72]

Long-term prognosis improves with follow-up testing after the initial episode, medication adjustments, and behavioral interventions. Adherence to colorectal cancer screening is particularly important. [73]

In inflammatory and ischemic colitis, the prognosis is determined by monitoring the underlying process: exacerbations and relapses require joint management with a gastroenterologist and proctologist. [74]

FAQ

Are these really hemorrhoids? I have scarlet blood on the paper.
Not necessarily. Yes, hemorrhoids are a common cause, but without an examination and, if indicated, an endoscopy, you can miss a fissure, polyp, or colitis. If episodes recur, if you're over 50, or if there are any "red flags," an in-person evaluation is necessary. [75]

When to perform a CTA and when a colonoscopy?
If severe bleeding continues, a CTA is performed first to quickly identify the source and refer for embolization. If the bleeding subsides and the patient is stable, a colonoscopy is performed on a non-emergency basis after preparation. [76]

What is the threshold for blood transfusion?
A restrictive approach is typically used, with a threshold of approximately 7 g/dL hemoglobin (higher thresholds are used in cases of myocardial ischemia and other special conditions). The decision is individualized based on the clinical presentation. [77]

If the cause is a diverticulum, will it recur?
It's possible. The risk of recurrence is present. The correct approach is endoscopic hemostasis or embolization if necessary, discontinuation of nonsteroidal anti-inflammatory drugs, and reconsideration of aspirin for primary prevention. [78]

Is it possible to avoid hospitalization?
Mild, one-time episodes in young patients without risk factors are often treated on an outpatient basis. However, in cases of heavy bleeding, weakness, anemia, age over 50, or taking anticoagulants, inpatient evaluation is better, according to recommendations. [79]

Table 6. Brief algorithm of actions for the patient

Situation	What to do now	What to discuss with your doctor
Traces of scarlet blood on the paper, no pain or weakness	Schedule a doctor's appointment and avoid sitting on the toilet for long periods of time.	Examination, possibly anoscopy; diet and fiber plan
A lot of scarlet blood, weakness, dizziness	Calling an ambulance	Hospitalization, CTA/colonoscopy, transfusion strategy
Blood + diarrhea/pain	Urgent in-person assessment	Colonoscopy, tests for infection/inflammation
Blood against the background of anticoagulants/NSAIDs	Contact a doctor/ambulance if there is a lot of blood	Drug adjustment/discontinuation, resumption plan
Based on current recommendations. [80]