Causes of anal fissure

Causes of Anal Fissure: Why the Anal Lining Tears

An anal fissure is a small tear in the delicate lining of the anal canal - and in almost every case, the cause is mechanical: something hard and dry forced its way through a passage that was too tight to receive it, per NHS guidance on anal fissure.

The Direct Causes

• Constipation and hard stools - the cause in the large majority of cases. A single hard, dry motion can split the lining
• Straining - prolonged pushing, often from low-fibre diets, low water intake, or ignoring the urge
• Chronic diarrhoea - repeated loose motions inflame and weaken the lining until it tears
• Childbirth - pressure and stretching during delivery commonly cause fissures in new mothers
• Anal intercourse or injury - direct trauma to the canal lining
• Tight sphincter muscle - in many people the internal anal sphincter rests too tight; this reduces blood flow to the area, which is why fissures heal slowly and recur

Less Common Causes Worth Knowing

Most fissures are simple mechanical tears. But a fissure that sits off the midline, fails to heal, or comes with other symptoms can signal an underlying condition - Crohn's disease, infections, or rarely cancer. That is one reason a persistent or unusual fissure deserves a doctor's examination rather than endless home treatment.

The Ayurvedic View: Parikartika

Classical texts call this condition Parikartika - literally "an encircling cutting pain." Interestingly, Charaka Samhita (Siddhi Sthana 6-7) describes it as a complication of overly drastic purgation or harsh enemas, while Bhavaprakasha links it to chronic constipation (Vibandha) and hard stools (Purisha-baddha) - the same mechanical logic modern medicine uses.

The classical chain: dry diet, suppressed urges and strain aggravate Apana Vayu (the Vata sub-type governing evacuation) and dry out the anal canal (Guda-vali). A hard stool then tears the unlubricated lining, producing the characteristic slicing pain. The frame is interpretive, but its practical advice - keep stools soft, never suppress urges, avoid excessive drying and purging - matches modern prevention advice closely.

Frequently Asked Questions

Can stress cause an anal fissure? Indirectly - stress alters bowel habits and can drive constipation or spasm. The tear itself is always mechanical.

Do spicy foods cause fissures? They do not cause the tear, but they can irritate an existing one and intensify burning during motions.

Why does my fissure keep coming back? Usually because the underlying cause - hard stools or a tight sphincter - was never fully corrected. Healing the tear without fixing the stool pattern invites recurrence.

Is an anal fissure the same as piles? No. Piles (hemorrhoids) are swollen veins; a fissure is a tear in the lining. They can coexist, and both can bleed - a doctor can tell them apart quickly.