Barrier occlusive therapy

Occlusive therapy means deliberately covering skin with a water-resistant layer so moisture cannot evaporate freely. In skincare this usually takes the form of an ointment or balm rich in petrolatum, lanolin, waxes or silicones, applied over damp or freshly moisturised skin. Slugging is the best-known consumer form of it — an overnight balm layer on the face — while occlusive therapy is the broader principle, applied to hands, body or skin under dressings, sometimes on clinical advice.

The rationale is straightforward: reducing transepidermal water loss keeps the stratum corneum better hydrated, and a well-hydrated surface is a more favourable environment for the skin's own repair processes. Occlusion also increases how much of whatever sits underneath is absorbed — useful with a bland moisturiser, but a clear reason for caution with anything active.

Do not occlude over retinoids, exfoliating acids or prescription topicals unless a clinician has told you to, because the increased penetration can cause significant irritation. Heavy occlusion can trap sweat and worsen congestion on acne-prone or fungal-acne-prone skin. Apply with clean hands, and see a doctor for broken, weeping or possibly infected skin.