They're caused by constipation!?
What are anal fissure?
Anal fissure are tears in the skin (anal epithelium below the dentate line) near the exit of the anus. Skin in this area is torn by the passage of hard stool when constipated or by strong pressure during diarrhea, causing poor blood circulation around the anal canal. The anal epithelium below the dentate line has sensory nerves (nerves that feel pain) unlike the mucous membrane inside the anus, which can result in severe pain along with anal fissure.
It is said that many women experience anal fissure, which could be related to the possibility that many women limit their food intake when dieting, etc., resulting in constipation. Eating less food on a diet causes stool bulk to remain small which results in less stimulation on the intestinal tract, with a tendency to constipation. This causes harder stools which are difficult to evacuate, and can tear the anal epithelium when passing through the anus, resulting in anal fissure.
If you tend to be constipated, you can develop chronic anal fissure which may become worse over time. This could result in avoiding bowel movements because of the severe pain, triggering further constipation. Stool then becomes harder, which can easily tear the skin around the anus. This can turn into a vicious cycle, making symptoms worse, and anal fissure more difficult to cure.
Symptoms include severe pain and bleeding during bowel movements. Bleeding is a little, with just a small amount on toilet paper. The problem is the pain.
Because sensory nerves (nerves that feel pain) pass through the anal epithelium, you can feel severe pain when the stool passes the cuts and tears.
The pain can cause the internal sphincter muscle of the anus to convulsions, which is followed by a severe pain.