Anal and rectal ulcers

Anal and rectal ulcers are an important diagnostic consideration in individuals presenting with anorectal pain, bleeding, or discharge. Causes include infectious, inflammatory, malignant, or mechanical etiologies (e.g., benign conditions such as solitary rectal ulcer syndrome). Anorectal ulcers in young, sexually active individuals are frequently due to sexually transmitted infections (STIs). Depending on the underlying cause, abdominal symptoms, constitutional symptoms (e.g., weight loss, fever), and extraintestinal features (e.g., joint pain) may be present. Clinical evaluation includes digital rectal examination and assessment for red flags for anorectal ulcers. Diagnostic assessment begins with visualization (e.g., anoscopy or sigmoidoscopy) and STI testing (e.g., ulcer swabs and laboratory studies). Treatment of suspected STIs (e.g., genital herpes, syphilis) should be started while awaiting diagnostic confirmation. Further management is directed at the underlying cause.

Anal ulcers in young, sexually active individuals are frequently due to STIs (e.g., genital herpes or syphilis). ^[1]

Focused history ^[1][11]

• Local symptoms
  • Anorectal pain: severity, timing (e.g., defecation-related)
  • Discharge and/or bleeding
  • Abnormal defecation: pain, urgency, straining, tenesmus
• Abdominal symptoms: constipation, symptoms of infectious gastroenteritis
• Constitutional symptoms: weight loss, fever
• Extraintestinal features: aphthous ulcers, joint pain, rash ^[3][4][5]
• Background
  • Past medical history: IBD, STIs, immunocompromise (e.g., HIV infection)
  • Medication review: NSAIDs, immunosuppressants, laxatives
  • Sexual history, including receptive anal intercourse

Focused examination ^[1][14][15]

• Perianal examination
  • Inspection
    • Ulcer size, depth, location, and color
    • Presence of blood or discharge
    • Other skin lesions
  • Digital rectal examination
• Systemic examination
  • Inguinal lymph node examination
  • Consider examination of other systems based on clinical features (e.g., abdominal examination, musculoskeletal examination).

Consider procedural sedation for digital rectal examination and/or anoscopy. ^[14]

Red flags for anorectal ulcers ^[4][16]

See also "Red flags for colorectal cancer" and "Clinical features of inflammatory bowel disease."

• Hematochezia
• Abdominal pain
• Altered bowel habits: diarrhea, constipation
• Unintentional weight loss
• Malaise, fatigue
• Fever

Approach ^[1]

• Confirm the presence of anorectal ulcers with direct visualization (e.g., anoscopy and/or sigmoidoscopy).
• Perform initial studies, including STI testing.
• Refer urgently to gastroenterology or surgery if red flag features for anorectal ulcers are present.

Consider empiric management of STIs while awaiting diagnostic results.

Infectious studies ^[1]

• All patients
  • Ulcer swabs for STI testing
  • Gram stain of anorectal exudate (if present): may support infectious cause (e.g., presence of granulocytes)
  • Serological studies
    • Syphilis serology
    • HIV testing ^[1]
    • Type-specific HSV serology (HSV-1 and HSV-2) ^[1]
• Patients with rectal ulcers: Stool diagnostic studies (e.g., stool microscopy and culture) may show leucocytes and/or identify pathogens.

Additional studies ^{[3][4][7][17]}

Further workup for noninfectious causes is considered if symptoms persist or initial studies are negative.

• Biopsy: for ulcers that are atypical or unresponsive to initial treatment
• Laboratory studies: to identify markers of systemic illness
  • CBC, BNP, CRP, albumin
  • Stool studies: fecal calprotectin to screen for IBD
• Cross-sectional imaging (e.g., CT or MRI): for suspected anal or rectal cancer
• Colonoscopy: to evaluate for IBD

General principles ^[1]

• Consider empiric management of STIs based on the most probable infection(s) while awaiting diagnostic results.
• Refer to gastroenterology or surgery if ulcers are atypical or unresponsive to treatment.
• Definitive management is based on the etiology.
• Advise against sexual activity until the patient and their partner(s) have been treated.
• Follow local protocols for notifying and managing sexual partners of patients with confirmed STI.

Empiric treatment ^[1][18]

Early treatment of suspected STIs reduces transmission risk and improves outcomes.

• Anal ulcers
  • Consider starting treatment of syphilis while awaiting diagnostic results.
  • PLUS treatment of genital herpes if painful ulcers are preceded by vesicles or recurrent
• Rectal ulcers
  • Consider starting empiric antibiotics for acute proctitis (i.e., ceftriaxone, doxycycline) while awaiting diagnostic results
  • PLUS treatment of genital herpes if painful ulcers are preceded by vesicles or recurrent

• Mimics of anal ulcers
  • Anal fissure
  • Anal fistula
  • Hemorrhoids
  • Rectal prolapse
• Mimics of rectal ulcers ^[19][20][21]
  • Rectal endometriosis
  • Proctitis
  • Colonic diverticulosis
  • Acute mesenteric ischemia

Solitary rectal ulcer syndrome is a benign condition characterized by one or more ulcerative lesions in the rectum, often associated with disordered defecation.

Etiology ^[11]

• Not completely understood
• Associated with:
  • Pelvic floor dyssynergia
  • Constipation and/or chronic straining
  • Internal rectal prolapse

Clinical features ^[11]

• Rectal bleeding
• Rectal pain
• Constipation
• Straining
• Tenesmus

Diagnosis ^[11]

• Sigmoidoscopy
  • Anterior rectal wall ulcer(s): may be solitary or multiple
  • Erythematous rectal wall patch(es)
  • Mucosal polypoid lesions
• Histopathology: confirms diagnosis and excludes conditions such as IBD or malignancy

Treatment ^[11]

Approach is based on the clinical picture and may include the following:

• Patient education: high-fiber diet, hydration, regular defecation timing, and avoidance of straining
• Pelvic floor biofeedback training
• Pharmacotherapy: laxatives