Merck Manual

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Parswa Ansari

, MD, Hofstra Northwell-Lenox Hill Hospital, New York

Reviewed/Revised Jan 2023
Topic Resources

Hemorrhoids are dilated vessels of the hemorrhoidal plexus in the anal canal. Symptoms include irritation and bleeding. Thrombosed hemorrhoids are usually painful. Diagnosis is by inspection or anoscopy. Treatment is symptomatic or with rubber banding, injection sclerotherapy, infrared photocoagulation, or sometimes surgery.

Increased pressure in the veins of the anorectal area leads to hemorrhoids. This pressure may result from pregnancy, frequent heavy lifting, or repeated straining during defecation (eg, due to constipation). Hemorrhoids may be external or internal. In a few people, rectal varices result from increased blood pressure in the portal vein, and these are distinct from hemorrhoids.

External hemorrhoids are located below the dentate line and are covered by squamous epithelium.

Internal hemorrhoids are located above the dentate line and are lined by rectal mucosa. Hemorrhoids typically occur in the right anterior, right posterior, and left lateral zones. They occur in adults and children.

Symptoms and Signs of Hemorrhoids

External hemorrhoids may become thrombosed, resulting in a painful, purplish swelling. Rarely, they ulcerate and cause minor bleeding. Cleansing the anal region may be difficult.

Internal hemorrhoids typically manifest with bleeding after defecation; blood is noted on toilet tissue and sometimes in the toilet bowl. Internal hemorrhoids may be uncomfortable but are not as painful as thrombosed external hemorrhoids. Internal hemorrhoids sometimes cause mucus discharge and a sensation of incomplete evacuation.

Strangulated hemorrhoids occur when protrusion and constriction occlude the blood supply. They cause pain that is occasionally followed by necrosis and ulceration.

Diagnosis of Hemorrhoids

  • Anoscopy

  • Sometimes sigmoidoscopy or colonoscopy

Most painful hemorrhoids, thrombosed, ulcerated, or not, are seen on inspection of the anus and rectum.

Anoscopy is essential in evaluating painless or bleeding hemorrhoids. Rectal bleeding should be attributed to hemorrhoids only after more serious conditions are excluded (ie, by sigmoidoscopy or colonoscopy).

Internal hemorrhoids can be classified by grade according to certain features (see table Classification of Internal Hemorrhoids Classification of Internal Hemorrhoids Classification of Internal Hemorrhoids ), which can help guide treatment.


Classification of Internal Hemorrhoids




Prominent hemorrhoids

No prolapse


Prolapse after a Valsalva maneuver

Prolapse reduces spontaneously


Prolapse after a Valsalva maneuver

Prolapse needs manual reduction


Chronic prolapse

Manual reduction of prolapse ineffective

Adapted from the American Society of Colon and Rectal Surgeons’ 2018 clinical practice guidelines for the management of hemorrhoids.

Pearls & Pitfalls

  • Exclude other, more serious causes before attributing rectal bleeding to hemorrhoids.

Treatment of Hemorrhoids

  • Symptomatic: Stool softeners, sitz baths, analgesics

  • Occasionally excision for thrombosed external hemorrhoids

  • Injection sclerotherapy, rubber band ligation, or infrared photocoagulation for internal hemorrhoids

(See also the American Society of Colon and Rectal Surgeons’ [ASCRS] 2018 clinical practice guidelines for the management of hemorrhoids.)

Symptomatic treatment

Symptomatic treatment of hemorrhoids is usually all that is needed. It is accomplished with stool softeners (eg, docusate, psyllium), warm sitz baths (ie, sitting in a tub of tolerably hot water for 10 minutes) after each bowel movement and as needed, anesthetic ointments containing lidocaine, or witch hazel (hamamelis) compresses (which soothe by an unknown mechanism). Pain caused by a thrombosed external hemorrhoid can be treated with nonsteroidal anti-inflammatory drugs.

Office-based procedures

Infrequently, simple excision of the external thrombosed hemorrhoid is done, which may relieve pain rapidly; after infiltration with 1% lidocaine, the thrombosed portion of the hemorrhoid is excised, and the defect is closed with an absorbable suture.

Patients with grades I and II internal hemorrhoids and some patients with grade III internal hemorrhoids (see table Classification of Internal Hemorrhoids Classification of Internal Hemorrhoids Classification of Internal Hemorrhoids ) who do not respond to symptomatic treatment can often be treated effectively with the following office-based procedures (see also the ASCRS 2018 clinical practice guidelines).

Injection sclerotherapy with 5% phenol in vegetable oil or other sclerosing agents can be used to treat bleeding internal hemorrhoids. Bleeding should cease at least temporarily.

Rubber band ligation is used for larger, prolapsing internal hemorrhoids, bleeding internal hemorrhoids, or those that do not respond to conservative management. With mixed internal and external hemorrhoids, only the internal component should be rubber band–ligated. The internal hemorrhoid is grasped and withdrawn through a stretched ½-cm diameter band, which is released to ligate the hemorrhoid, resulting in its necrosis and sloughing. Typically, one hemorrhoid is ligated every 2 weeks; 3 to 6 treatments may be required. Sometimes, multiple hemorrhoids can be ligated at a single visit, but this may cause more pain. External hemorrhoids should not be banded.

Infrared photocoagulation is useful for ablating nonprolapsing, bleeding internal hemorrhoids, or hemorrhoids that are not cured with rubber band ligation.

Surgical hemorrhoidectomy

Surgical hemorrhoidectomy is required for patients who do not respond to other forms of therapy and for those who have grade IV internal hemorrhoids. Significant postoperative pain is common, as are urinary retention and constipation.

Stapled hemorrhoidopexy is an alternative procedure for circumferential hemorrhoids and causes less postoperative pain but has higher recurrence and complication rates than conventional surgical hemorrhoidectomy.

How To Do Hemorrhoidal Thrombectomy

Other procedures

Doppler-guided hemorrhoid artery ligation, in which a rectal ultrasound probe is used to identify vessels for suture ligation, is promising but requires further study to determine its overall utility.

Laser destruction, cryotherapy, and various types of electrodestruction are of unproven efficacy.

Key Points

  • External hemorrhoids may thrombose and become very painful but rarely bleed.

  • Internal hemorrhoids often bleed but are not often painful.

  • Stool softeners, topical treatments, and analgesics are usually adequate treatment for external hemorrhoids.

  • Bleeding internal hemorrhoids may require injection sclerotherapy, rubber band ligation, or infrared photocoagulation.

  • Surgery is a last resort.

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

Drugs Mentioned In This Article

Drug Name Select Trade
BeneHealth Stool Softner, Colace, Colace Clear, Correctol, D.O.S., DC, Diocto, Doc-Q-Lace, Docu Liquid, DocuLace, Docusoft S, DocuSol, DocuSol Kids, DOK, DOK Extra Strength, Dulcolax, Dulcolax Pink, Enemeez, ENEMEEZ Kids, Fleet Pedia-Lax, Genasoft, Kaopectate Liqui-Gels, Kao-Tin , Phillips Stool Softener, Plus PHARMA, Silace, Stool Softener , Stool Softener DC, Stool Softener Extra Strength, Sulfolax, Surfak, Sur-Q-Lax , Uni-Ease , VACUANT
Fiber Therapy, GenFiber , Geri-Mucil, Hydrocil , Konsyl, Metamucil, Metamucil MultiHealth, Mucilin , Natural Fiber Laxative, Natural Fiber Therapy, Reguloid
7T Lido, Akten , ALOCANE, ANASTIA, AneCream, Anestacon, Aspercreme with Lidocaine, AsperFlex, Astero , BenGay, Blue Tube, Blue-Emu, CidalEaze, DermacinRx Lidocan III, DermacinRx Lidogel, DermacinRx Lidorex, DERMALID, Dologesic, Ela-Max, GEN7T, Glydo, Gold Bond, LidaFlex, LidaMantle, Lido King Maximum Strength, Lidocan, Lidocare, Lidoderm, LidoDose, LidoDose Pediatric, Lidofore, LidoHeal-90, LIDO-K , LidoLite, Lidomar , Lidomark, LidoPure, LidoReal-30, LidoRx, Lidosense 4 , Lidosense 5, Lidosol, Lidosol-50, LIDO-SORB, Lidotral, Lidovix L, LIDOZION, Lidozo, LMX 4, LMX 4 with Tegaderm, LMX 5, LTA, Lubricaine For Her, Lydexa, Moxicaine, Numbonex, ReadySharp Lidocaine, RectaSmoothe, RectiCare, Salonpas Lidocaine, Senatec, Solarcaine, SUN BURNT PLUS, Tranzarel, Xyliderm, Xylocaine, Xylocaine Dental, Xylocaine in Dextrose, Xylocaine MPF, Xylocaine Topical, Xylocaine Topical Jelly, Xylocaine Topical Solution, Xylocaine Viscous, Zilactin-L, Zingo, Zionodi, ZTlido
Hemorrhoidal , Medi-Pads, Preparation H for Women Medicated Hemorrhoidal, Preparation H Maximum Strength, Preparation H Totables, Sani-Pads with Aloe, Tucks, Tucks Take Along
Castellani Paint, Chloraseptic, Chloraseptic Kids, Phenaseptic, Sore Throat
NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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