The Location: The highly sensitive anal canal
The last section of the digestive tract is the anal canal (about 3 – 6 cm long). It is located between the rectum (the storage site for stool) and the anus (anal opening). The anal canal is closed by two circular sphincter muscles. These, together with the hemorrhoidal zone, seal the intestine from the outside world. The anal canal is lined with extremely delicate skin, the highly sensitive anoderm. Its dense network of nerves “detects” whether gas, hard, or soft stool is reaching the anal opening. This nerve network is the reason why conditions in the anal area can be extremely painful, such as an anal fissure or hemorrhoids (see below).
An anal fissure can occur at any age
An anal fissure is a tear in the highly sensitive skin of the anal canal (anoderm), usually in a longitudinal direction. An anal fissure manifests as severe, sometimes stabbing and/or burning pain during bowel movements, which can last for hours afterward. Bright red blood on the stool or toilet paper is common. Itching or burning at the anal opening can also indicate an anal fissure. Medicine distinguishes between acute and chronic (lasting longer than six weeks) anal fissures.
Main cause of anal fissure: Constipation
An acute anal fissure most often occurs during the passage of hard and/or bulky stool. This overstretches the delicate skin of the anal canal, causing painful tearing. Many acute anal fissures heal on their own. If this does not happen, the affected individuals often find themselves in a vicious cycle. Due to the pain during bowel movements, they delay going to the toilet, which causes the stool to harden further, and the anal fissure to tear even deeper during the next bowel movement. Additional cramping of the sphincter muscle reduces blood flow to the anal canal, delaying wound healing. If the cycle is not broken, an acute anal fissure can develop into a chronic one.
Other causes of anal fissure
An anal fissure can occur whenever the skin of the anal canal is severely strained and/or already damaged by a chronic condition. Not only hard stool but also chronic diarrhea increases the risk of an anal fissure. Therefore, many people with Crohn’s disease suffer from painful tears in the anal canal. Hemorrhoids also increase the risk of an anal fissure. Certain sexual practices (anal intercourse) can also be triggers.
Hemorrhoidal Disease: A common condition in industrialized nations
About 70% of all adults experience hemorrhoidal disease, or simply hemorrhoids, at some point in their lives—men more often than women. Hemorrhoids are more likely to occur due to hereditary predisposition (connective tissue weakness), a low-fiber diet (e.g., fast food), sedentary jobs without physical activity, hard stool and excessive straining during bowel movements, as well as pregnancy.
The term hemorrhoids refers to nodular enlargements (hemorrhoidal nodes) of the blood vessels in the hemorrhoidal zone, classified into four grades of severity. Depending on the severity of the hemorrhoidal nodes, symptoms may include bright red blood on the stool or toilet paper, itching, inflammation, moisture, and swelling at the anal opening, as well as pain during bowel movements and a feeling of incomplete evacuation. An anal canal damaged by hemorrhoids is prone to developing anal fissures. Treatment for hemorrhoids depends on their severity.
Skin tags are harmless and not painful
Skin tags are small flaps of skin that protrude from the delicate skin of the anal canal and emerge from the anal opening. Unlike hemorrhoids, they contain no blood vessels and cause no anal discomfort. Common causes include pregnancy, an anal vein thrombosis (perianal thrombosis), or a chronic anal fissure. Advanced hemorrhoidal disease can also push the anoderm (delicate skin in the anal canal) out of the anal opening in the form of skin tags. Skin tags can be surgically removed (but do not have to be), especially if they make anal hygiene difficult or are cosmetically bothersome to the individual.
Diarrhea irritates the delicate skin in the anal area
Stool contains aggressive substances that can damage the skin barrier of the anal opening and its surroundings. Painful burning is the result—especially with frequent and/or prolonged contact with stool due to diarrhea or fecal incontinence (uncontrolled passage of stool). Common causes of diarrhea include illnesses (e.g., gastrointestinal infections, Crohn’s disease), medications (e.g., antibiotics, laxatives, certain chemotherapy drugs), or a colonoscopy as part of colorectal cancer screening.
When the skin barrier is already damaged, even brief contact with stool can be very painful—for example, with an anal fissure, after surgery, or after the removal of genital warts in the anogenital area.
Essential: Careful anal hygiene and skin protection
Anal conditions should be evaluated by a general practitioner or a specialist in proctology (“proktós” in Greek means “anus”). Regardless of whether medical treatment is necessary or not, anyone with an anal condition should pay attention to meticulous anal hygiene. This is particularly important when removing stool residues is difficult (e.g., with skin tags or hemorrhoids) and/or when minimizing contact with stool is essential (e.g., with an anal fissure, surgical wound).
