An anal fissure is a small tear in the anoderm, the specialized lining of the anal canal, often occurring just inside the anal opening. While not generally considered a serious medical problem, a fissure can cause considerable discomfort and significantly impact a person’s quality of life. The condition is often acute, appearing suddenly and healing relatively quickly. However, it can become chronic if the tear fails to heal after several weeks. This article clarifies the symptoms, investigates the underlying causes, and provides steps for achieving relief.
Understanding Symptoms Including Pain and Itching
The hallmark symptom of an anal fissure is intense, sharp pain during a bowel movement, often described as a tearing or burning sensation. This initial, severe pain is frequently followed by a dull, throbbing ache that can persist for minutes or hours due to spasms in the internal anal sphincter muscle. The affected area is highly innervated, which explains the severity of the discomfort even from a small tear.
Anal fissures can cause itching, medically termed pruritus ani, as a frequent secondary symptom. While the fissure primarily causes pain, the subsequent irritation, inflammation, and moisture around the wound lead to an intense urge to scratch. This itching often results from minor discharge or seepage that irritates the perianal skin, triggering the classic “itch-scratch-itch” cycle. Scratching only further inflames the delicate skin and prolongs the irritation.
The fissure also causes a small amount of bright red blood to appear on the toilet paper or on the surface of the stool. This bleeding is typically minor and occurs because the tissue is constantly reopened by the passage of waste.
Primary Causes and Risk Factors
The most common cause of an anal fissure is mechanical trauma from passing large or hard stool during a bowel movement. Excessively firm stool stretches the anal canal beyond its capacity, tearing the fragile anoderm. Straining, often due to constipation, significantly increases internal pressure and the risk of tissue damage.
Chronic diarrhea can also be a cause, as the frequent passage of loose, irritating stools increases moisture and repeated wiping erodes the protective lining. A high resting pressure in the internal anal sphincter muscle, known as hypertonia, contributes to chronic fissures. This muscle spasm reduces blood flow to the area, hindering the oxygen and nutrients needed for proper healing.
Other factors that increase susceptibility include:
- Childbirth, due to intense physical strain and trauma to the anal tissues.
- Underlying medical conditions, such as Crohn’s disease, which causes chronic inflammation.
- Engaging in anal intercourse.
- Inserting foreign objects into the anus.
Effective Non-Surgical Relief Strategies
Management of an anal fissure focuses on non-surgical methods to soften the stool and reduce internal pressure from anal sphincter spasm. Dietary modification is foundational, requiring 25 to 35 grams of fiber per day to add bulk and softness to the stool. Adequate hydration, typically eight to ten glasses of water daily, works synergistically with fiber to prevent stools from becoming hard and dry.
Stool softeners, such as docusate sodium, can temporarily ease waste passage and minimize straining. Sitz baths, soaking the anal area in warm water for 10 to 20 minutes several times a day, help relax the spastic internal anal sphincter muscle. This warmth reduces pain and promotes increased blood flow for healing.
For localized pain relief, over-the-counter topical anesthetic creams containing lidocaine can be applied. If these initial conservative measures do not lead to healing, a physician may prescribe specialized topical medications designed to relax the anal muscle. These include nitroglycerin ointment or creams containing calcium channel blockers (nifedipine or diltiazem), which reduce sphincter tone and improve blood supply.
If symptoms persist beyond six to eight weeks, the fissure is considered chronic and requires professional consultation. Further treatments include an injection of botulinum toxin into the internal sphincter muscle to induce temporary paralysis and allow healing. If all other non-surgical strategies fail to provide lasting relief, a minor surgical procedure may be considered to resolve persistent muscle tension.