Chronic dry skin: moisturisers are the evidence-backed fix, but effects are modest

Chronic dry skin — the medical name is xerosis — is skin that has lost too much water and the oils that hold water in. It shows up as tightness, roughness, flaking, fine cracks and itch, and it gets worse in winter, with age, and with anything that strips the skin: hot showers, harsh soaps, low humidity. The single most useful thing to understand is that it is a barrier problem, not a hygiene problem. Washing more does not fix dry skin; it usually makes it worse. What repairs the barrier is putting oil and water-binding ingredients back on the skin, regularly.

Why skin gets dry

The outer layer of skin works like a brick wall — cells held together by a mortar of lipids that keeps water in. When that mortar is depleted, water evaporates faster than the skin can replace it, the surface stiffens and fissures, and nerve endings become easier to irritate, which is why dry skin itches. Ageing thins this layer and slows lipid production, which is why xerosis is so common in older adults; medical causes such as an underactive thyroid, kidney disease and some medicines can drive it too.

What actually helps: emollients

The best randomised evidence on whether moisturising dry, inflamed skin works comes from a Cochrane review of 77 studies with 6,603 participants, in people with eczema — the condition where dry skin has been most rigorously tested [s1]. Six of those trials compared using a moisturiser against using none at all, and the results are a useful reality check: they show real benefits, but measured ones.

Moisturiser use produced lower disease-severity scores than no moisturiser (three studies, 276 participants, mean difference in SCORAD −2.42, 95% confidence interval −4.55 to −0.28), although that difference did not reach the threshold considered clinically important, a minimal important difference of 8.7 [s1]. Where the payoff showed clearly was in flares and treatment burden. People using moisturisers had far fewer flares (two studies, 87 participants, risk ratio 0.40, 95% confidence interval 0.23 to 0.70), their skin took much longer to flare (a median of 180 versus 30 days), and they needed less topical steroid (two studies, 222 participants, mean difference −9.30 g, 95% confidence interval −15.3 to −3.27) [s1]. A steroid-sparing effect of that size is the practical case for daily moisturising: it is not just comfort, it reduces how much stronger medicine you need.

Specific formulations did more than bland ones in the review. With the emollient Atopiclair, 174 of 232 participants improved versus 27 of 158 on the inactive vehicle (risk ratio 4.51, 95% confidence interval 2.19 to 9.29), and it reduced itching (four studies, 396 participants, mean difference −2.65, 95% confidence interval −4.21 to −1.09) [s1]. Ingredients that bind water or mimic skin lipids — such as urea, glycerol and ceramides — are what separate an effective moisturiser from a cosmetic one, and the evidence quality across these outcomes was rated low, so the direction is clearer than the precise size [s1].

The evidence in older skin is thin

For the group most affected — frail older people — the evidence is surprisingly weak. A separate Cochrane review of six trials in 1,598 care-home residents found that current evidence about hygiene and emollients for maintaining skin integrity is inadequate [s2]. The one trial that measured skin damage, in 984 residents, found the emollient group (usual care plus twice-daily moisturiser) had 5.76 skin tears per month per 1,000 occupied bed-days compared with 10.57 in the usual-care-only group (P = 0.004) — a near-halving, but on very low-quality evidence, so the reviewers were uncertain of the result [s2]. Emollient regimens did appear to reduce clinical dryness scores versus no treatment, again on low-quality evidence [s2].

A routine that matches the evidence

The plan that fits the data is unglamorous and consistent: wash less aggressively with lukewarm water and a gentle, non-soap cleanser; pat dry; and apply a thick, fragrance-free moisturiser containing a humectant such as urea or glycerol, ideally within a few minutes of washing and at least twice a day. Thicker ointments and creams outperform thin lotions on very dry skin. The gains come from doing it every day, not from any single premium product.

See a doctor if dry skin is severe, cracked and bleeding, suddenly worse, widespread with intense itch that disturbs sleep, or accompanied by weight change, fatigue or swelling — generalised xerosis can occasionally be the visible sign of thyroid, kidney or other systemic disease rather than simple winter skin.

This article is informational and is not medical advice.

Sources

• [s1] Emollients and moisturisers for eczema — Cochrane Database of Systematic Reviews, 6 February 2017. https://doi.org/10.1002/14651858.CD012119.pub2
• [s2] Hygiene and emollient interventions for maintaining skin integrity in older people in hospital and residential care settings — Cochrane Database of Systematic Reviews, 23 January 2020. https://doi.org/10.1002/14651858.CD011377.pub2