Rectal Disorders: Common Anorectal Problems Explained

The rectum and anus: a quick map

The rectum is the last 12 to 15 cm (about 5 to 6 inches) of the large bowel, where stool is stored. It ends at the anal canal, about 4 cm long, surrounded by two sphincter muscles that control continence. The dentate line inside the anal canal is an important landmark: above it there are few pain nerves, below it the skin is very sensitive. That is why internal hemorrhoids bleed painlessly, while fissures and external hemorrhoids hurt.

Common rectal disorders

Matching symptoms to likely causes

Rectal bleeding

Bright red blood on the paper or in the bowl most often comes from hemorrhoids or a fissure. Darker blood mixed with stool, clots, or bleeding with a change in bowel habit suggests a source higher up, such as polyps, inflammatory bowel disease or colorectal cancer. See rectal bleeding for a full guide.

Pain

• Sharp pain with each bowel movement: fissure
• Sudden painful lump at the anal edge: thrombosed external hemorrhoid
• Constant throbbing pain with swelling and fever: abscess
• Brief, intense cramp-like pain at night, with normal exam: proctalgia fugax, a harmless muscle spasm
• Dull, aching pressure for hours, worse sitting: levator ani syndrome, a pelvic floor muscle disorder

Itching

Usually from moisture, over-cleaning, scented wipes, coffee, spicy food, hemorrhoids or skin conditions such as eczema or psoriasis. In children, pinworms are a common cause.

A lump

Hemorrhoids, skin tags, abscess, warts, prolapse or, less often, a tumor.

Discharge

Mucus from prolapsed hemorrhoids or proctitis; pus from a fistula; stool leakage from incontinence.

Causes and risk factors

• Constipation and straining, low-fiber diet and prolonged sitting on the toilet
• Chronic diarrhea
• Pregnancy and vaginal childbirth, which can stretch or tear the sphincter and pelvic floor
• Crohn's disease and ulcerative colitis, which cause fistulas, fissures and proctitis
• Sexually transmitted infections, including gonorrhea, chlamydia, herpes, syphilis and HPV
• Aging, weak pelvic floor and nerve damage (diabetes, spinal problems)
• Radiation therapy to the pelvis
• Family history of colorectal cancer or polyps

How rectal disorders are diagnosed

1. History: bowel habits, bleeding pattern, pain timing, diet, medicines, sexual history and family history.
2. Visual inspection of the anal area.
3. Digital rectal exam: a gloved, lubricated finger checks for masses, tenderness and sphincter tone.
4. Anoscopy or proctoscopy: a short scope to view the anal canal and lower rectum in the office.
5. Flexible sigmoidoscopy or colonoscopy: for bleeding in people 45 and older, those with risk factors or warning signs, and for screening.
6. Specialized tests: anorectal manometry and balloon expulsion test for pelvic floor problems and incontinence, endoanal ultrasound or MRI for fistulas and sphincter injury, swabs for STIs.

Treatment overview

Treatment depends on the cause, but some measures help most benign anorectal problems:

• Fiber: 25 to 35 g a day from food or a supplement such as psyllium, with plenty of fluids, to make stools soft and easy to pass.
• Toilet habits: go when you feel the urge, avoid straining and limit time on the toilet to a few minutes (no phone).
• Sitz baths: sitting in a few inches of warm water for 10 to 15 minutes, 2 to 3 times a day, eases pain and spasm.
• Gentle hygiene: rinse with water, pat dry, avoid scented wipes and soaps.
• Topical treatments: hemorrhoid creams for short periods; prescription creams that relax the sphincter for fissures.

Specific treatments include rubber band ligation for hemorrhoids, botulinum toxin or sphincterotomy for chronic fissures, drainage for abscesses, fistula surgery, biofeedback therapy for pelvic floor dysfunction, and surgery for prolapse. Cancer is treated with surgery, radiotherapy and chemotherapy.

Prevention

• eat a high-fiber diet and stay hydrated
• stay active and maintain a healthy weight
• treat constipation and diarrhea early
• use condoms to reduce anal STIs, and consider HPV vaccination
• start colorectal cancer screening at 45, or earlier with a family history

Frequently asked questions

What are the most common rectal disorders?

Hemorrhoids are the most common, followed by anal fissures, anal itching (pruritus ani), perianal abscesses and fistulas. Rectal prolapse, proctitis, fecal incontinence and pelvic floor dysfunction are less common. Colorectal and anal cancers are important but less frequent causes of symptoms.

When should I worry about rectal bleeding?

See a doctor for any rectal bleeding that recurs, is dark or mixed with stool, comes with a change in bowel habit, weight loss, tiredness or anemia, or occurs if you are 45 or older. Heavy bleeding with dizziness is an emergency.

How do I know if it is a hemorrhoid or a fissure?

Hemorrhoids usually cause painless bright red bleeding, sometimes with a soft lump or itching. A fissure causes sharp, tearing pain during a bowel movement that can last an hour or more afterward, with a little bright red blood. A doctor can tell them apart with a simple exam.

Which doctor treats rectal problems?

Start with your primary care doctor, who can examine you and treat many common problems. You may be referred to a gastroenterologist for colonoscopy or bowel conditions, or a colorectal surgeon for fissures, fistulas, abscesses, prolapse and hemorrhoids that need procedures.

Can rectal disorders go away on their own?

Many minor ones do. Small hemorrhoids, acute fissures and mild itching often heal within days to weeks with fiber, fluids, sitz baths and gentle hygiene. Abscesses, fistulas, prolapse and chronic fissures usually need medical treatment.