Hemorrhoids are normal vascular cushions in the anal canal composed of dilated vascular tissue, smooth muscle, and connective tissue. They do not cause issues unless they are enlarged, inflamed, thrombosed, or prolapsed. Patients often present with rectal bleeding of bright red blood, or they may have pain, perianal pruritus, or a palpable mass. Risk factors include family history, low-fiber diet, and constipation. The two main types of hemorrhoids are external, usually with perianal pain, and internal, which are usually painless. The main diagnostic tools are history, physical exam, and endoscopic procedures if indicated for further investigation. If symptoms are acute, excision can be performed for external hemorrhoids. Otherwise, conservative management is recommended. Surgical methods are reserved for more severe hemorrhoids or those unresponsive to primary treatment.

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Hemorrhoids are normal swollen vascular structures in the anorectal canal.

  • Vascular cushions that assist with stool passage: 
    • Originate from channel of arteriovenous connective tissues
    • Composed of vascular tissue, smooth muscle, and connective tissue
  • Venous cushions with rich vascular supply 
  • Drain into superior and inferior hemorrhoidal veins


  • Worldwide estimated prevalence: 4.4%
  • Prevalence increases with age: peak at 45–65 years old
  • Hemorrhoids affect up to 10 million patients in the United States annually.
    • Upwards of ⅓ of these patients seek medical care. 
    • About 40% of patients are asymptomatic. 
  • No known sex predilection 
  • Present more frequently in:
    • People of higher socioeconomic backgrounds 
    • Those living in rural areas 
    • Caucasian race


  • Decreased venous return with increased pressure engorging hemorrhoids: 
    • Straining during defecation 
    • Pregnancy-related anatomical compression
    • Aging-related weakening of pelvic support structures 
    • Prolonged sitting on toilet
  • Portal hypertension with anorectal varices: usually in the midrectum, where portal system and inferior/middle rectal veins meet
  • Other risk factors:
    • Chronic diarrhea
    • Constipation 
    • Colon malignancy
    • Inflammatory bowel disease
    • Obesity
    • Spinal cord injury
    • Rectal surgery
    • Episiotomy
    • Anal intercourse
External and internal hemorrhoids

Depiction of internal hemorrhoids above the dentate line and external hemorrhoid, likely causing pain, below the dentate line

Image: “Anus with hemorrhoids” by Bruce Blaus. License: CC BY 3.0



  • Hemorrhoids become symptomatic when enlarged, inflamed, thrombosed, or prolapsed.
  • Hemorrhoidal veins are located in the submucosal layer in the lower rectum.
    • Arise from a plexus or cushion of dilated arteriovenous channels and connective tissue 
    • May be external or internally located based on position in relation to dentate line

External hemorrhoids

  • Below the dentate (pectinate) line
  • Arise from the inferior hemorrhoidal plexus
  • Covered by modified squamous epithelium with somatic pain receptors 
  • Innervated by pudendal nerve and sacral plexus
  • Acute thrombosis pathogenesis: 
    • Extreme pain caused by skin distention and edema
    • Caused by straining, diarrhea, or constipation 
    • Can persist as excess skin tags after healing
    • Usually last 7–14 days

Internal hemorrhoids

  • Above the dentate line
  • Unclear pathogenesis; possible theories include:
    • Deterioration of connective tissue anchoring hemorrhoids 
    • Hypertrophy or increased internal anal sphincter tone 
    • Abnormal arteriovenous distention within hemorrhoidal cushions
    • Abnormal dilation of internal hemorrhoidal venous plexus
  • Not supplied by somatic sensory nerves; usually painless
Anal canal anatomy

Anatomy of the anal canal:
The image shows the pectinate (dentate) line, which marks the area separating the origination of external (below the dentate line ) and internal (above the dentate line) hemorrhoids.

Image by Lecturio.

Clinical Presentation

External hemorrhoids

  • Acutely painful rectal bleeding with associated bowel movement 
  • Perianal pain:
    • Likely from acute thrombosis 
    • Prolapsed or strangulated hemorrhoids 
  • Painful mass at the rectum or feeling of fullness 
  • May also have painful, irritated skin tags (redundant fibrotic skin) near the rectum

Internal hemorrhoids

  • Usually painless, with bright red blood from rectum associated with bowel movement 
  • Can be associated with mucous discharge and itching of perianal skin 
  • May have associated fecal incontinence and leakage 
  • Wetness or fullness sensation at the perianal area for prolapsed internal hemorrhoid


Physical examination

  • Best patient position: left lateral decubitus, knees to chest
  • On visual inspection, check for:
    • Fissures, dermatitis, skin tags, thromboses
    • Intact sensation (anoderm folds and wink)
    • Signs of infection or abscesses
    • Prolapse: bluish and tender mass around the anus
  • On digital rectal exam, check for:
    • Ulcers, masses, tenderness
    • Discharge (e.g., mucus), blood
    • Rectal tone
    • Internal hemorrhoids (palpable when thrombosed)
  • Internal hemorrhoid grading: 
    • Grade I: prominent hemorrhoidal vessels without prolapse 
    • Grade II: prolapse with Valsalva maneuver with spontaneous reduction
    • Grade III: prolapse with Valsalva maneuver with manual reduction
    • Grade IV: chronically prolapsed with ineffective manual reduction

Laboratory studies and procedures

  • Order CBC if anemia or iron deficiency is suspected.
  • Procedures: 
    • Anoscopy when no hemorrhoid detected on physical exam:
      • Rapid bedside procedure for direct visualization 
      • Evaluate the anal canal and distal rectum.
      • Internal hemorrhoids will appear as bulging purple-blue veins.
      • Thrombosed external hemorrhoids will be acutely tender and have a purple hue.
    • Flexible sigmoidoscopy or colonoscopy based on risk factors for rectal bleeding:
      • Patients > 40 years old with risk factors for colorectal cancer 
      • Patients > 50 years old without a colonoscopy within the past 10 years 
      • Unusual rectal bleeding unlikely to be from hemorrhoids


Treatment approach

  • Treat only symptomatic patients.
  • Counsel dietary modifications such as avoiding fatty foods.
  • Distinguish between external and internal hemorrhoids:
    • Visceral innervation of internal hemorrhoids → less pain
    • Somatic innervation of external hemorrhoids → sensitive to pain, thus generally would require surgery with anesthesia if initial management fails
  • Evaluate for emergency or nonemergency care:
    • Emergency care:
      • Excise acutely thrombosed external hemorrhoid.
      • Instill local anesthetic and create elliptical excision of thrombosed hemorrhoid.
      • If 72 hours or more after onset of symptoms → conservative management
    • Conservative management (for grade I internal and nonthrombosed external hemorrhoids):
      • Warm baths to relax anal sphincter
      • Improve toilet habits with no prolonged sitting.
      • Ice for acute thrombosis
      • Increase dietary fiber and fluid intake.
      • Stool softeners such as docusate sodium
      • Topical analgesics such as lidocaine 
      • Topical corticosteroids 
      • Topical nifedipine and nitroglycerin to relieve anal sphincter spasms

Nonsurgical procedures

The following procedures are for grades I and II internal hemorrhoids that do not respond to conservative management.

  • Rubber band ligation: 
    • Band ligature passed via anoscope; causes tissue necrosis
    • Hemorrhoid sloughs off in 1–2 weeks.
  • Electrocoagulation:
    • Bipolar electrocautery coagulates the hemorrhoid tissue.
    • Excellent control of pain 
  • Sclerotherapy:
    • Indicated for early internal hemorrhoids 
    • Provides chemical sclerosis
    • Higher rate of posttreatment pain and recurrence rates 
    • Not commonly used
  • Cryotherapy: freezing of hemorrhoids 
  • Radiowave and laser ablation with suture ligation:
    • Costly, but effective for prolapsing hemorrhoids 
    • Associated with recurrence


  • Coagulopathy
  • Portal hypertension
  • AIDS and other immunodeficiency disorders
  • Inflammatory bowel disease (IBD)
  • Pregnancy and immediate postpartum period
  • Large fissure or infection
  • Tumor
  • Prolapse of rectal wall

Surgical treatment


  • Open approach or minimally invasive laser approach
  • Indicated if other treatments have failed
  • Symptomatic grade III and IV hemorrhoids or severe external hemorrhoids
  • Presence of other local conditions

Other options:

  • Stapled hemorrhoid surgery:
    • For large internal hemorrhoids that are prolapsed 
    • Requires specialized device
  • Doppler-guided transanal hemorrhoidal dearterialization:
    • For grade II prolapsing hemorrhoids 
    • Device identifies and subsequently ligates the blood supply.

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Differential Diagnosis

  • Anal fissure: a superficial tear in the anoderm, associated with constipation, trauma, or IBD: Patients present with rectal pain with bowel movements, passage of bright-red blood, and some spasm. Diagnosis is via physical exam and history. Treatment is usually conservative, with increasing fluids and fiber intake, warm sitz baths, and stool softeners. Topical nifedipine helps with anal spasms, and local anesthetics provide pain control. 
  • Acute proctitis: inflammation of the rectal mucosa, can be caused by antibiotics, STDs, and autoimmune GI diseases: Patients can present with anal and rectal pain, diarrhea, abdominal pain, mucus discharge, rectal bleeding, and tenesmus. Diagnosis is via history, physical exam, and workup of etiology such as infectious or radiation-induced inflammation. Treatment is aimed at symptom control as well as treating the inciting factor. If infection-related, metronidazole is most commonly used. 
  • Colorectal cancer: oncologic process of the colon and/or rectum, with patients usually presenting with painless bleeding from the rectum with a bowel movement: Colorectal cancer may manifest with weight loss, a rectal mass, abdominal pain, and/or anemia. Diagnosis is via clinical presentation, physical exam, colonoscopy, and cross-sectional CT imaging. Treatment is multimodal, with a combination of surgery and chemotherapy based on disease staging.


  1. Bleday, R. (2019). Home and office treatment of symptomatic hemorrhoids. UpToDate. Retrieved February 21, 2021, from https://www.uptodate.com/contents/home-and-office-treatment-of-symptomatic-hemorrhoids
  2. Bleday, R. (2020). Hemorrhoids: Clinical manifestations and diagnosis. UpToDate. Retrieved February 21, 2021, from https://www.uptodate.com/contents/hemorrhoids-clinical-manifestations-and-diagnosis
  3. Perry, K. (2019). Hemorrhoids. Medscape. Retrieved February 21, 2021, from https://emedicine.medscape.com/article/775407-overview

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