Transepidermal water loss
Pronunciation: trans-ep-ih-DER-mal WAY-ter loss
Also written as: TEWL — Transepidermal water loss
The passive diffusion of water through the epidermis and its subsequent evaporation, used as an objective measure of skin-barrier function.
Full Definition
Transepidermal water loss (TEWL) quantifies the integrity of the epidermal barrier by measuring the rate at which water escapes through the skin surface. Elevated TEWL indicates barrier disruption and is commonly assessed in paediatric patients with atopic tendencies, neonatal skin conditions, or inherited keratinisation disorders. TEWL is expressed in g/m²/h and is measured using a tewameter or similar closed-chamber device. In editorial contexts, the abbreviation TEWL appears frequently in clinical trial reports and must be spelled out on first use per most style guides.
Usage
Usage note: Spell out in full at first mention; thereafter TEWL is universally understood in dermatology literature.
In Context
- "Baseline transepidermal water loss measurements were obtained at enrolment to quantify skin-barrier disruption in the neonatal cohort." — Clinical research protocol
- "A significant reduction in TEWL was observed following eight weeks of twice-daily emollient application." — Randomised controlled trial results section