A fissure is a small tear or crack in skin or tissue. The term shows up most often in two contexts: anal fissures, which are tears in the lining of the anal canal, and skin fissures, which are deep cracks that form in dry, damaged skin on the hands, feet, or heels. A less common but related use is “fissured tongue,” a harmless condition where grooves develop on the tongue’s surface. Each type has different causes and treatments, but they all share that basic definition: a split in tissue that shouldn’t be there.
Anal Fissures: The Most Common Type
An anal fissure is a tear in the thin, delicate lining of the anal canal. It’s one of the most common anorectal conditions, and it causes sharp pain during bowel movements along with small amounts of bright red blood on toilet paper or on the surface of the stool. The tear almost always appears at the posterior midline, the back of the anal opening, where blood flow is less than half that of other parts of the canal. That poor circulation is a big part of why these tears can be stubborn to heal.
Fissures are classified as either acute or chronic. Acute fissures are shallow tears that typically heal within six weeks with basic care. Chronic fissures are those that persist beyond six to eight weeks, often because repeated injury and muscle spasm create a cycle that prevents the tissue from repairing itself.
What Causes Anal Fissures
The most straightforward cause is passing a hard, large stool. Constipation is the leading trigger, but chronic diarrhea can also irritate the tissue enough to cause a tear. Other causes include childbirth-related trauma, prior anal surgery, and inflammatory bowel disease. In less common cases, infections or anal cancer can produce fissures that look different from the typical ones, appearing off the midline or in unusual locations.
What makes many fissures hard to resolve is a feedback loop involving the internal anal sphincter, the ring of muscle that controls the opening. In people with fissures, this muscle tends to be tighter than normal. The elevated pressure squeezes blood vessels and reduces circulation to the already vulnerable tissue. Less blood flow means slower healing, and the unhealed tear triggers more muscle spasm, which further reduces blood flow. That cycle is what turns an acute fissure into a chronic one.
How Anal Fissures Are Treated
Most acute fissures heal on their own with simple changes. The goal is to soften stools and reduce strain. That means getting 25 to 30 grams of fiber daily from fruits, vegetables, nuts, and whole grains, or from a fiber supplement if your diet falls short. Drinking plenty of fluids and exercising regularly both help keep bowel movements soft and consistent. Regular exercise also improves blood flow throughout the body, which supports healing. Warm sitz baths, sitting in a few inches of warm water for 10 to 15 minutes, can relax the sphincter and ease pain after a bowel movement.
When conservative measures aren’t enough, prescription ointments can help by relaxing the sphincter muscle and improving blood flow to the tear. These topical treatments are applied twice daily for up to eight weeks. If the fissure still won’t heal, surgery becomes an option. The standard procedure involves making a small cut in the internal sphincter muscle to permanently reduce its resting pressure. This approach heals about 90% of chronic fissures with a recurrence rate below 10%, though it does carry some risk of affecting bowel control afterward.
Skin Fissures on Hands and Feet
Skin fissures are deep cracks that form when the outer layer of skin loses too much moisture. They’re most common on the heels, fingertips, and between the toes, areas that experience mechanical stress and have relatively few oil-producing glands. The lower legs, forearms, hands, and feet are all particularly prone.
The underlying problem is a breakdown in the skin’s barrier function. When the outermost layer of skin dries out, its cells don’t shed properly, the surface becomes rough and scaly, and eventually the skin splits. Cold, dry weather, frequent handwashing, harsh soaps, and conditions like eczema or psoriasis all accelerate this process. In severe cases, the cracks extend deep enough to bleed and become painful.
Treatment focuses on restoring moisture and repairing the skin barrier. Thick moisturizers or ointments applied regularly are the first line of defense, ideally right after washing while the skin is still slightly damp. Products containing urea or dexpanthenol are particularly effective for fissures that have already formed. Preventing skin fissures comes down to protecting vulnerable areas: wearing gloves in cold weather or when using cleaning products, switching to gentle cleansers, and moisturizing consistently before the skin reaches the cracking stage.
Fissured Tongue
A fissured tongue is a different condition entirely. It’s an inherited trait in which the surface of the tongue develops grooves that vary in size and depth. It’s usually noticed incidentally during a dental exam and almost never causes symptoms unless food debris gets trapped in the grooves, which can occasionally lead to a burning sensation or mild irritation.
No treatment is needed for a fissured tongue. Gentle brushing of the tongue’s surface can help clear out debris and prevent any discomfort. The condition has been observed alongside certain syndromes, including Down syndrome and Melkersson-Rosenthal syndrome, but in the vast majority of people it exists on its own and is completely benign.
Preventing Fissures From Coming Back
For anal fissures, prevention is really about long-term bowel habits. Hitting that 25 to 30 grams of daily fiber target, staying well hydrated, and exercising regularly are the most reliable ways to keep stools soft enough that they pass without straining. Avoiding prolonged sitting on the toilet and not ignoring the urge to go also help reduce pressure on the anal canal.
For skin fissures, the key is consistency with moisturizing before the skin gets dry enough to crack. People who are prone to heel fissures benefit from using a thick cream nightly and wearing socks to lock in moisture. Those who wash their hands frequently, including healthcare workers and food service employees, should apply a barrier cream or ointment after each wash. In both cases, the pattern is the same: the easiest fissure to treat is the one you prevent.