Cracked heels form when the skin on the bottom of your foot becomes thick, dry, and rigid enough that it splits under the pressure of walking and standing. The process starts with callus buildup and ends with visible fissures that can range from cosmetically annoying to deep enough to bleed. Understanding what drives that process helps you figure out which causes apply to you and what to do about them.
How Heel Cracks Actually Form
Your heel bears a concentrated share of your body weight with every step. When the skin there is healthy and flexible, it stretches to absorb that force. But when something disrupts the skin’s moisture barrier, whether from friction, dryness, or an underlying condition, the body responds by producing extra layers of tough, protective skin cells. That thickened skin is what you see as a callus.
The problem is that this protective response backfires. The thickened tissue is rigid and poorly hydrated, so it can’t flex the way normal skin does when you walk. Repeated pressure triggers an inflammatory cycle: microscopic breaks form in the skin’s outer lipid layer, the body responds by pushing out even more skin cells, and those cells don’t fully mature before they stack up. The result is a stiff, brittle surface. Under continued weight-bearing, that surface cracks along linear fault lines, the same way dried mud splits in the sun. Once a fissure starts, each step pulls it wider and deeper.
Footwear and Mechanical Stress
The single most common external trigger is the way your foot moves inside your shoe. Open-back sandals, flip-flops, and any loose-fitting footwear let the heel slide around and rub against the sole with each step. As podiatric surgeon Sara Rose-Sauld of Mass General Brigham has explained, all that friction signals the body to build thicker skin on the heels as a defense mechanism. The irony is that the thicker the skin gets, the more likely it is to crack.
Standing for long stretches on hard surfaces has a similar effect. Jobs that keep you on your feet for eight or more hours a day expose the heel pad to sustained compression, accelerating callus formation. Going barefoot frequently also removes the cushioning layer between skin and ground, increasing both friction and impact.
Dry Skin and Lost Moisture
Heel skin is naturally drier than most of your body because the soles of your feet have no oil glands. They rely entirely on sweat glands for moisture. Anything that reduces that moisture, or strips it away faster than it’s replaced, sets the stage for fissures.
Low humidity, cold weather, and long hot showers all pull water out of the skin. Soaps and detergents dissolve the thin lipid film that helps skin hold onto moisture. Age matters too: as you get older, your skin produces fewer natural moisturizing compounds, and cell turnover slows, making it easier for dead, dry layers to accumulate on the heels.
Medical Conditions That Contribute
Several health conditions make cracked heels significantly worse or harder to resolve.
Diabetes. Nerve damage from diabetes (autonomic neuropathy) can disrupt the sweat glands in the feet, causing them to produce less moisture than usual. That leaves the skin chronically dry. Because neuropathy also reduces sensation, people with diabetes may not notice early cracking until fissures are already deep. This is why foot care guidelines for diabetics specifically emphasize daily moisturizing to prevent cracking.
Hypothyroidism. An underactive thyroid slows metabolism throughout the body, including in the skin. Reduced thyroid hormone levels lead to less oil and sweat production, resulting in widespread dryness that tends to concentrate on areas already prone to it, like the heels.
Eczema and psoriasis. Both conditions can affect the soles of the feet, causing patches of inflamed, scaly skin that crack more easily under pressure. If your heel fissures appear alongside red, itchy, or flaky patches elsewhere on your body, one of these conditions may be the underlying driver.
Palmoplantar keratoderma. This is a less common condition where the skin on the palms and soles becomes abnormally thick, hard, yellow, and flaky, often with deep fissures. It can be inherited or acquired later in life. It’s diagnosed based on physical appearance and medical history, and sometimes requires a skin biopsy or blood tests to identify the underlying cause. If standard moisturizing and exfoliation don’t improve your heels at all, this is worth investigating.
Vitamin Deficiencies That Affect Heel Skin
Nutritional gaps can weaken the skin barrier enough to make cracking more likely, especially when combined with mechanical stress.
Vitamin C is essential for collagen production, and collagen makes up about 75% of the dry weight of the deeper layer of your skin. Without enough vitamin C, skin loses its ability to retain moisture and repair itself. Severe deficiency (scurvy) causes dry, scaly skin, slow wound healing, and easy bruising, but even moderate insufficiency can leave heel skin drier and more fragile.
Vitamin E acts as an antioxidant that protects collagen from breakdown. It helps counteract the drying effect that aging has on skin. Low levels allow the skin to dry out and lose elasticity faster, which on the heels translates directly to higher fissure risk.
Vitamin B3 (niacin) plays a role in energy metabolism and skin barrier function. Significant deficiency causes pellagra, a condition marked by dry, scaly skin that can develop on the heels and other areas. Pellagra is rare in developed countries but can occur in people with very restricted diets or certain digestive conditions that impair nutrient absorption.
Obesity and Body Weight
More body weight means more downward force on the heel pad with every step. That force flattens the fat pad under the heel, pushing it outward and stretching the skin sideways. If the skin is already dry or thickened, that lateral expansion is what creates the initial crack. This is why weight loss, even modest amounts, often improves heel fissures that haven’t responded to moisturizing alone.
How to Manage and Prevent Cracking
The core strategy is straightforward: soften the skin, reduce the thickness, and keep moisture locked in.
Urea-based creams are the standard recommendation for cracked heels. Urea draws water into the skin and softens the hardened outer layer. Concentrations of 5% and 20% both improve skin hydration compared to plain cream, though 20% urea creams tend to deliver slightly more hydration overall. For mild dryness, a 5% cream applied daily is often enough. For thick calluses and visible cracks, starting with a 20% to 25% cream helps break down the buildup faster. Apply it right after bathing, when your skin is still slightly damp, and cover your feet with socks to help the cream absorb.
Gentle exfoliation with a pumice stone removes dead skin and keeps calluses from reaching the point where they crack. Use it on damp skin, with light circular motions, a few times a week. Over-filing is a real risk: if you remove too much skin, you can cause bleeding and open the door to infection. Stop immediately if you feel pain, see redness, or break the skin.
Switching to closed-back shoes with cushioned insoles reduces the friction and impact that trigger callus formation in the first place. If you stand for long periods at work, supportive shoes with shock-absorbing soles make a measurable difference over time.
When Cracks Become Dangerous
Most heel fissures are a nuisance, not a medical emergency. But deep cracks can bleed and become entry points for bacteria. An infected heel fissure can progress to cellulitis, a spreading skin infection that causes redness, warmth, swelling, and sometimes fever. People with diabetes or compromised immune systems are at higher risk for this progression because their bodies are slower to fight off infection and heal wounds.
Signs that a crack has become infected include increasing pain, pus or cloudy discharge, a foul smell, expanding redness around the fissure, or warmth that spreads beyond the crack itself. If you notice these, the fissure needs medical attention rather than just a thicker layer of moisturizer.