Lateral fissure treated as primary fissure without evaluation for secondary causes
Digital rectal exam attempted despite severe pain and sphincter spasm
Persistent symptoms beyond 6 to 8 weeks without escalation to second-line therapy or colorectal referral
Differential Diagnosis
Primary anorectal pain and bleeding
Common alternatives
Hemorrhoids
Internal hemorrhoids with painless bleeding
Thrombosed external hemorrhoid with acute pain
Perianal abscess or fistula
Deep ache, fever, drainage
Proctitis
Infectious proctitis
Radiation proctitis
Anal trauma
Instrumentation-related injury
Foreign body injury
Secondary fissure etiologies and serious mimics
Serious and secondary causes
Crohn disease with perianal involvement
Multiple or lateral fissures
Fistula or abscess
Sexually transmitted infections
HSV
Syphilis
Gonorrhea or chlamydia proctitis
Malignancy
Anal squamous cell carcinoma
Dermatologic inflammatory disease
Lichen sclerosus
Contact dermatitis
Coding aligned list
ICD-10 K60.0 acute anal fissure
ICD-10 K60.1 chronic anal fissure
ICD-10 K60.2 anal fissure unspecified
Laboratory Tests
Labs for complications and alternatives
Laboratory triage
No routine labs for classic uncomplicated fissure
Typical posterior midline fissure with minimal bleeding
Complete blood count for significant bleeding concern
Symptomatic anemia concern
Persistent moderate bleeding
C-reactive protein for inflammatory concern
Suspected IBD flare features
Suspected deep infection features
Basic metabolic panel for dehydration or renal risk
Significant diarrhea
Poor oral intake
Infectious and secondary cause testing
Targeted testing
Pregnancy test when relevant
Medication safety planning
STI testing when risk or proctitis features
NAAT for gonorrhea and chlamydia
Syphilis serology
HSV testing if vesicles or ulcers
HIV testing when indicated
Immunosuppression concern
High-risk exposure history
Interpretation and limitations
Result use
Normal labs do not exclude perianal abscess
Clinical exam remains primary
Elevated inflammatory markers support secondary process
IBD or infection evaluation pathway
Diagnostic Tests
Scoring Systems
Symptom and bowel pattern tools
Pain scale
Baseline pain score for response tracking
Post-defecation pain duration tracking
Bristol Stool Form Scale
Type 1 to 2 supports constipation contribution
Type 6 to 7 supports diarrhea contribution
Constipation severity history
Straining frequency
Incomplete evacuation sensation
MRI
MRI pelvis indications
Suspected complex perianal disease
Recurrent abscess
Suspected fistula
Suspected Crohn perianal involvement
Multiple or lateral fissures
Chronic drainage
Concern for malignancy extent
Indurated lesion
CT
CT abdomen and pelvis indications
Suspected deep pelvic sepsis
Systemic toxicity
Severe pain out of proportion
Suspected perirectal abscess not defined on exam
Deep rectal pain
Fever with minimal perianal findings
Alternate intraabdominal source concern
Significant abdominal pain with rectal symptoms
Ultrasound
Ultrasound applications
Perianal ultrasound
Superficial abscess characterization when exam equivocal
Endoanal ultrasound
Sphincter integrity assessment before surgery in selected patients
High incontinence risk planning
Disposition
ED and outpatient pathways
Disposition decisions
Discharge appropriate
Typical fissure appearance
Minimal bleeding
Pain controlled with topical and oral options
Able to tolerate oral intake and bowel regimen
Urgent colorectal surgery follow-up
Symptoms beyond 6 weeks
Recurrent fissure pattern
Failure of first-line therapy after 6 to 8 weeks
Same-day surgical evaluation
Suspected abscess
Concern for necrotizing infection
Concern for malignancy on exam
Admission consideration
Sepsis physiology
Uncontrolled pain requiring parenteral analgesia
Significant bleeding with symptomatic anemia concern
Follow-up timing
Follow-up targets
Primary care follow-up within 1 to 2 weeks
Stool regimen adherence check
Symptom improvement review
Colorectal surgery follow-up within 2 to 6 weeks
Chronic fissure features
Atypical fissure location
Second-line therapy planning
Treatment
First-line conservative care
Core regimen
Fiber supplementation
Psyllium or equivalent daily
Titrate to soft formed stool
Osmotic stool softener
Polyethylene glycol 17 g daily
Titrate to 1 soft stool daily
Sitz baths
Warm water 10 to 15 minutes after bowel movement
Additional 1 to 2 times daily for spasm relief
Topical anesthetic
Lidocaine 2% to 5% topical before bowel movement
Short course to reduce discomfort and enable defecation
Avoidance targets
Straining
Prolonged time on toilet
Constipating medications when feasible
Topical sphincter relaxation therapy
Nitric oxide donor option
Glyceryl trinitrate ointment 0.2% to 0.4%
Small amount to anal verge twice daily
Duration up to 6 to 8 weeks
Adverse effects headache and hypotension risk
Contraindication concurrent PDE-5 inhibitor use
Calcium channel blocker option
Diltiazem 2% topical
Small amount to affected area twice daily
Duration commonly 6 to 8 weeks
Use case intolerance or nonresponse to glyceryl trinitrate
Evidence framing
Topical pharmacotherapy supported as first-line for chronic fissure in ASCRS guidance
Strong recommendation language varies by guideline
Treat as Class I recommendation for chronic fissure medical therapy based on guideline consensus
Treat as ACEP Level C equivalent for ED disposition guidance and follow-up timing
Botulinum toxin injection
Indications and expectations
Chronic fissure with failure of topical therapy
Persistent symptoms beyond 6 to 8 weeks despite adherence
Botulinum toxin into internal anal sphincter
Technique and dose per colorectal surgery protocol
Comparable to topical therapies as first-line in some guidance
Adverse effects
Transient sphincter weakness risk
Surgical therapy
Lateral internal sphincterotomy
Highest healing rates for chronic fissure in comparative literature
Consider after failure of medical options and shared decision-making
Incontinence risk counseling
Flatus incontinence risk most common postoperative issue
High-risk incontinence patients
Consider alternatives such as advancement flap or tailored sphincterotomy per colorectal surgery plan
Analgesia and supportive care
Pain control
Acetaminophen oral
Maximum daily dose per local policy
NSAID oral if appropriate
Avoid if renal risk or significant GI bleed risk
Opioid avoidance
Constipation worsening risk
If required, mandatory bowel regimen escalation
Special Populations
Pregnancy
Pregnancy considerations
Constipation prevention emphasized
Fiber and osmotic stool softener favored
Hydration and activity as tolerated
Medication safety planning
Prefer conservative regimen first
Topical therapies used with obstetric awareness when needed
Postpartum context
Perineal trauma and constipation common triggers
Early stool softening to prevent recurrence
Geriatric
Older adult considerations
Secondary cause vigilance
Malignancy concern with atypical lesion
Chronic ulceration requiring evaluation
Higher dehydration and renal risk
Stool softener titration with electrolyte monitoring when indicated
Incontinence risk baseline assessment
Prior obstetric injury
Prior anorectal surgery
Neurologic disease
Pediatrics
Pediatric considerations
Constipation as dominant driver
Behavioral toileting plan
Osmotic laxative weight-based per pediatric protocol
Safeguarding considerations when indicated
Trauma history inconsistent with presentation
Diltiazem 2% topical described in evidence summaries including children and young people
Background
Epidemiology
Frequency and context
Common benign anorectal condition
Often associated with constipation or diarrhea
Typical location
Posterior midline most common
Anterior midline more common in women and pregnancy context
Pathophysiology
Mechanism
Linear tear in anoderm
Trauma from hard stool or frequent stooling
Internal anal sphincter spasm
Reduced anodermal perfusion
Impaired healing cycle
Chronic fissure changes
Sentinel skin tag
Fibrosis and exposed sphincter fibers
Therapeutic Considerations
Rationale for therapies
Stool softening and fiber
Reduce recurrent mechanical trauma
Warm sitz baths
Reduce sphincter spasm and pain perception
Topical vasodilators and calcium channel blockers
Lower resting sphincter pressure
Improve local blood flow to promote healing
Botulinum toxin
Chemical sphincter relaxation
Lateral internal sphincterotomy
Durable reduction in sphincter hypertonicity with highest healing rates in many series
Patient Discharge Instructions
copy discharge instructions
Discharge text
Diagnosis anal fissure
Goal soft stool daily without straining
Fiber supplement daily with water
Polyethylene glycol daily until stool soft then adjust dose
Warm sitz baths 10 to 15 minutes after bowel movements and 1 to 2 more times daily
Topical lidocaine before bowel movements as needed for pain
If prescribed topical diltiazem or glyceryl trinitrate, apply small amount twice daily for up to 6 to 8 weeks
Headache or dizziness possible with glyceryl trinitrate
Avoid prolonged sitting on toilet and avoid straining
Follow-up with primary care in 1 to 2 weeks
Colorectal surgery follow-up if symptoms not improving within 2 to 4 weeks or if symptoms persist beyond 6 weeks
Return to ED immediately
Fever
Worsening perineal pain or swelling
Pus or new drainage
Large or persistent rectal bleeding
Lightheadedness or fainting
New anal mass or rapidly worsening pain
References
Guidelines and evidence
Key sources
ASCRS Clinical Practice Guidelines for the Management of Anal Fissures 2023
ASCRS Toolkit Management of Anal Fissures updated content
NICE evidence summary for unlicensed 2% topical diltiazem for chronic anal fissure
StatPearls Anal Fissures overview and adverse effects
WHO ICD-10 browse K60 fissure and fistula of anal and rectal regions
ICD-10-CM K60.0 K60.1 K60.2 code definitions
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