Dry, flaky skin happens when your skin’s outermost layer loses moisture faster than it can replace it. The underlying cause can be as simple as low humidity or harsh soap, or it can signal a nutrient deficiency or chronic skin condition. In most cases, something has disrupted the thin barrier of natural oils that normally keeps water locked inside your skin cells.
How Your Skin’s Moisture Barrier Works
The outermost layer of your skin, just 10 to 20 cells thick, is the only thing standing between your body’s internal water supply and the dry air around you. This layer works because of a specific mixture of fats packed between the cells: ceramides make up about 50% of these fats, cholesterol accounts for roughly 25%, and fatty acids contribute about 10%. Together, they form tightly organized sheets that water can’t easily pass through.
Ceramides and fatty acids are rod-shaped molecules that pack together into rigid, dense layers, almost like interlocking tiles. Cholesterol sits between them and adds just enough flexibility to keep the whole structure from becoming brittle and cracking. When any of these components gets stripped away or stops being produced in the right amounts, gaps form in the barrier. Water escapes from inside your skin (a process called transepidermal water loss), and the surface cells dry out, curl up, and flake off.
This is the common thread behind nearly every cause of dry, flaky skin: something is either pulling fats out of that barrier, preventing your body from making them, or overwhelming the barrier’s ability to hold moisture in.
Environmental Triggers
Cold, dry air is the most common cause of seasonal flaking. Indoor humidity ideally sits between 30% and 50% for skin health, but forced-air heating in winter can push it well below that range. Low humidity pulls oils directly from your skin’s surface, stripping away the protective layer that slows water loss. This is why people who never deal with flaking in summer suddenly notice it on their shins, hands, and face once the heat kicks on.
Hot showers compound the problem. Prolonged exposure to hot water dissolves the same ceramides and fatty acids that form your moisture barrier. A five-minute lukewarm shower is far less damaging than a 15-minute hot one, especially in winter when your skin is already under stress. Wind and sun exposure also accelerate moisture loss from the skin’s surface, which is why outdoor workers and people in arid climates are particularly prone to flaking.
Soaps and Cleansers That Strip Your Skin
Healthy skin has a slightly acidic surface pH, typically between 4.5 and 5.5. Traditional bar soaps are alkaline, often with a pH of 9 or 10, and that mismatch disrupts the skin’s acid mantle, a thin acidic film that helps maintain the fat barrier underneath. Cleansers with a pH close to your skin’s natural range cause the least disruption.
The bigger issue is surfactants, the ingredients that make cleansers foam and cut through grease. Harsh surfactants form tiny structures called micelles that act like microscopic solvents, pulling ceramides and cholesterol directly out of the spaces between your skin cells. This is the same barrier-wrecking mechanism that causes dry air to trigger flaking, just delivered in liquid form. If your skin feels tight or squeaky after washing, the cleanser is removing more than dirt. Switching to a gentle, fragrance-free cleanser with a pH close to 5.5 is one of the simplest fixes for persistent flaking.
Aging and Hormonal Changes
Oil production from the sebaceous glands declines naturally with age, but the timeline is different for men and women. Women experience a gradual drop in oil production starting after menopause, as falling estrogen levels slow sebaceous gland activity. Men tend to maintain their oil production much longer, with a noticeable decrease often not occurring until after age 80. Less oil on the skin’s surface means less reinforcement for the moisture barrier, which is why dry, flaky patches become increasingly common in older adults, particularly on the lower legs, arms, and hands.
The skin also thins with age and produces fewer of the natural moisturizing factors that draw water into cells. These changes stack on top of the oil decline, making older skin more vulnerable to environmental triggers that younger skin could shrug off.
Nutritional Deficiencies
Several vitamin and mineral deficiencies produce dry, flaky skin as one of their earliest visible signs. Vitamin A deficiency causes rough, bumpy skin with hard plugs that project from hair follicles, sometimes described as “toad-like” in texture. These plugs typically appear on the buttocks and outer arms first.
Zinc deficiency can mimic eczema or psoriasis, producing scaly, inflamed patches especially around the mouth, on the hands and feet, and in the diaper area of infants. Adults need about 8 to 11 mg of zinc daily, and deficiency signs typically improve within two to three weeks of supplementation.
B vitamin deficiencies each leave their own signature on the skin. Low vitamin B2 (riboflavin) causes cracking at the corners of the mouth and scaly patches around the nose. Low B6 causes widespread dryness along with seborrheic dermatitis, the greasy flaking that appears on the scalp and face. Low B3 (niacin) produces the most dramatic changes: sharply defined, darkened, rough patches on sun-exposed skin that harden and become brittle. The disease it causes, pellagra, literally translates to “rough skin.”
Vitamin C deficiency leads to a different pattern, with corkscrew-shaped hairs, tiny hemorrhages around hair follicles, and poor wound healing. These nutritional causes are relatively uncommon in developed countries, but they’re worth considering if your dry skin doesn’t respond to moisturizers and environmental changes, or if it appears alongside fatigue, hair loss, or mouth sores.
Skin Conditions That Cause Flaking
Eczema
Eczema (atopic dermatitis) produces scaly, itchy patches that can appear virtually anywhere on the body. It results from a combination of genetic barrier defects and an overactive immune response. People with eczema often produce fewer ceramides than normal, leaving permanent weak spots in their skin’s moisture barrier. Flare-ups are triggered by irritants, allergens, stress, and dry air, and the itch-scratch cycle further damages the already compromised barrier.
Psoriasis
Psoriasis produces thick, well-defined plaques covered in silvery-white scale. Unlike the patchy, irregular flaking of dry skin, psoriasis plaques have sharp borders and tend to appear symmetrically on the elbows, knees, scalp, and lower back. The flaking comes from an immune-driven acceleration of skin cell turnover: cells that normally take about a month to mature and shed are pushed to the surface in just a few days, piling up into visible scales. A variant called guttate psoriasis appears as small, round, scaly spots scattered across the trunk, often triggered by a strep throat infection.
Seborrheic Dermatitis
Seborrheic dermatitis causes salmon-pink, flaky patches in oily areas: the scalp, eyebrows, creases beside the nose, behind the ears, and on the chest. It’s driven by an overgrowth of a yeast that feeds on skin oils, which is why it targets sebum-rich zones rather than the dry areas where other forms of flaking appear. Dandruff is a mild form of the same condition.
Other Common Contributors
Certain medications cause dryness as a side effect, particularly acne treatments that speed up skin cell turnover, cholesterol-lowering drugs, and blood pressure medications that act as diuretics. If flaking started shortly after beginning a new prescription, the timing is worth noting.
Dehydration from not drinking enough fluids can worsen skin dryness, though it rarely causes flaking on its own in otherwise healthy people. Thyroid disorders, particularly an underactive thyroid, slow down oil production and skin cell turnover, leading to dry, rough skin that’s often most noticeable on the shins. Diabetes and kidney disease can also produce widespread dryness by affecting how the body manages fluids and nutrients.
Overwashing and over-exfoliating deserve a mention because they’re self-inflicted and easy to reverse. Scrubbing flaky skin with abrasive exfoliants can temporarily remove visible flakes, but it also strips the barrier further, creating a cycle where the skin flakes more, prompting more scrubbing. Gentle cleansing followed by a ceramide-containing moisturizer applied to damp skin is consistently more effective than aggressive exfoliation at breaking that cycle.