title: Pathophysiologic basis for growth failure in children with ichthyosis: an evaluation of cutaneous ultrastructure, epidermal permeability barrier function, and energy expenditure.
abstract: OBJECTIVE
  Because an impaired epidermal permeability barrier is present in many of the ichthyoses, we examined the contribution of barrier failure to caloric requirements in children with ichthyosis and growth failure.
  
  
  METHODS
  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.
  
  
  RESULTS
  Mean basal TEWL rates were markedly elevated in all study patients in comparison to the expected upper limit of normal (39.6+/-20.6 vs 8.7 mL/m(2) 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 +/- 468 vs 209 mL/d), resulting in a caloric drain of 433 +/- 272 kcal/d (21 +/- 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).
  
  
  CONCLUSIONS
  A defective permeability barrier in children with ichthyosis can result in ample chronic losses of water and calories to impair growth.
authors.affiliation: Department of Dermatolog, University of California San Francisco, and the Department of Veterans Affairs Medical Center, San Francisco, 94143, USA.
authors.forename: David G
authors.initials: DG
authors.lastname: Moskowitz
authors.forename: Ashley J
authors.initials: AJ
authors.lastname: Fowler
authors.forename: Melvin B
authors.initials: MB
authors.lastname: Heyman
authors.forename: Sharon P
authors.initials: SP
authors.lastname: Cohen
authors.forename: Debra
authors.initials: D
authors.lastname: Crumrine
authors.forename: Peter M
authors.initials: PM
authors.lastname: Elias
authors.forename: Mary L
authors.initials: ML
authors.lastname: Williams
mesh_terms: D000293:Adolescent; D001481:Basal Metabolism / Q000502:physiology*; D002153:Calorimetry, Indirect; D002648:Child; D002675:Child, Preschool; D002149:Energy Intake / Q000502:physiology; D004817:Epidermis / Q000378:metabolism* / Q000503:physiopathology / Q000648:ultrastructure*; D005260:Female; D006130:Growth Disorders / Q000503:physiopathology*; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D007057:Ichthyosis / Q000503:physiopathology*; D008297:Male; D008853:Microscopy; D010539:Permeability; D012016:Reference Values; D013207:Staphylococcal Skin Infections / Q000188:drug therapy / Q000503:physiopathology; D014870:Water Loss, Insensible / Q000502:physiology*