Atopic dermatitis and daily moisturizing: what the guidance says

Atopic dermatitis involves a compromised skin barrier. Ceramide levels in the stratum corneum are reduced, which was reported as early as 1991 and remains a central explanation for atopic dry skin. With less of the intercellular lipid holding corneocytes together, water escapes faster and irritants penetrate more easily. Each cycle of irritation and recovery leaves the barrier a little weaker, which is why the condition tends to recur in the same places.

This is the reasoning behind emollients being described as the foundation of care rather than an adjunct. A Cochrane review of emollients and moisturizers for eczema found that they relieve symptoms, and that using them together with topical corticosteroids produced better results than corticosteroids alone.

This is where most routines fall short. Guidance for adults suggests at least 250 g of emollient per week, which is roughly 1,080 g per month, applied at least twice daily. Most people use a small fraction of that and then conclude the product does not work. Before changing products, it is worth checking the quantity.

A fingertip unit is the amount squeezed onto the pad of the index finger from the tip to the first crease, approximately 0.5 g. The measure was proposed by Long and Finlay in 1991 for topical corticosteroid dosing and is equally useful for gauging emollient quantity. A full-body application comes to roughly 20 g, so twice daily reaches about 280 g per week, which is where the guideline figure comes from.

Timing matters as much as quantity. Applying immediately after bathing, while the skin is still damp, helps retain water. Bathe in lukewarm water at around 27 to 30 degrees Celsius for five to ten minutes. Hot, prolonged washing strips surface lipids and leaves the skin drier than before.

Emollients do not replace treatment. Where topical corticosteroids have been prescribed, the two are used together, and the direction of dosing is opposite: prescribed steroids are used sparingly and for defined periods, while emollients are used generously and continuously. Reference figures for topical corticosteroid use are roughly 15 g per month for infants, 30 g for children and 60 to 90 g for adolescents and adults, which is an order of magnitude below the emollient figure.

On the question of which to apply first, a 2024 review concluded that established evidence is lacking. Treat any source that states a definitive order with caution, and follow the instruction of the prescribing clinician. Do not discontinue prescribed treatment because the skin has improved.

Most atopic dermatitis information is written around infants and children, where lesions typically begin on the cheeks and scalp and later move to flexural areas. In adults, lesions more often appear on the face, neck and hands, and chronic lesions become thickened and hyperpigmented. Differences in distribution and course between pediatric and adult disease are documented in the literature.

Practically, this changes what to buy. Adults typically need a lighter texture for the face, a large format for the body, and something portable for hands that are washed frequently. Adult-specific variables such as makeup removal, shaving and occupational exposure also have no equivalent in childhood care.