Transepidermal water loss (TEWL) and ultrastructural parameters of the permeability barrier were evaluated in 10 hospitalized children with ichthyosis and growth failure. Nutritional intake, resting energy expenditure, and calories lost as heat of evaporation were determined.
Mean basal TEWL rates were markedly elevated in all study patients in comparison to the expected upper limit of normal (39.6b1;20.6 vs 8.7 mL/m2 per hour). The severity of abnormalities in the ultrastructure of permeability barrier-related structures, assessed semiquantitatively, correlated significantly to mean basal TEWL rates (P <.001). Total body daily TEWL was elevated (746 b1; 468 vs 209 mL/d), resulting in a caloric drain of 433 b1; 272 kcal/d (21 b1; 9.8 kcal/kg per day) through heat of evaporation. Nutrient intake exceeded requirements in all, but resting energy expenditure exceeded predicted in 5 of 6 patients and correlated significantly with mean basal TEWL rates (P <.005).
A defective permeability barrier in children with ichthyosis can result in ample chronic losses of water and calories to impair growth.