Constipation

This condition involves having large, hard, dry stools that are difficult or painful to pass. Constipation increases the likelihood of lesions forming in the anal region during bowel movements.

Chronic Diarrhea

Prolonged diarrhea can lead to skin dryness and cracking around the anus. Since the skin in this area is highly sensitive, constant diarrhea may cause an anal fissure, resulting in significant pain.

Pregnancy and Childbirth

Pregnant women are more likely to develop anal fissures as the pregnancy progresses. Additionally, the tissues around the anus may tear during childbirth, contributing to the development of fissures.

Muscle Spasms

Spasms in the anal muscles can tear the inner lining of the anus during bowel movements, potentially leading to chronic anal fissures.

Anal Intercourse

Any trauma to the anal tissues, including rough anal intercourse or the insertion of objects into the anus, can overstretch the skin, causing an anal fissure.

HIV

For HIV-positive individuals, anal lesions associated with HIV can lead to debilitating pain during defecation. These lesions may be more severe and cause pain unrelated to bowel movements.

Tuberculosis

Anal tuberculosis can result in persistent, recurrent ulcer-like fissures in the anal region that do not heal.

Other Conditions

Several other conditions may contribute to anal fissures, including:

Crohn's Disease: An inflammatory bowel disease that causes inflammation in the digestive tract.
Ulcerative Colitis: An inflammatory bowel disease that leads to inflammation and ulcers in the digestive tract.
STDs: Sexually transmitted diseases such as syphilis, gonorrhea, chlamydia, and chancroid.
Minor Trauma: Injuries to the anal region caused by activities like mountain biking, or the insertion of a rectal thermometer, enema tip, or ultrasound probe.
Weight Loss Surgery: This procedure can result in explosive diarrhea, which may contribute to anal fissures.