BARRIER FUNCTION PARAMETERS IN VARIOUS KERATINIZATION DISORDERS - TRANSEPIDERMAL WATER-LOSS AND VASCULAR-RESPONSE TO HEXYL NICOTINATE

In this study, we characterized the stratum corneum barrier function i n 39 patients with various keratinization disorders (autosomal dominan t ichthyosis vulgaris [ADI] [n = 7], X-linked recessive ichthyosis [XR I] [n = 6], autosomal recessive congenital ichthyosis [CI] [n = 10], d yskeratosis follicularis [Darier's disease; DD] [n = 8], erythrokerato derma variabilis [EKV] [n = 8]), and 21 healthy volunteers, using two non-invasive methods: transepidermal water loss (TEWL) measuring outwa rd transport of water through the skin by evaporimetry, and the vascul ar response to hexyl nicotinate (HN) penetration into the skin as dete rmined by laser-Doppler flowmetry. Significantly increased TEWL values were found on the volar forearm in all three forms of ichthyosis, com pared with the healthy control group, with the highest TEWL values in the CI group. The penetration of HN on the volar forearm was accelerat ed in patients with ADI. XRI and CI, as indicated by a shorter lag tim e (t0) between HN application and initial vascular response. However, differentiation between CI and the other ichthyoses was not possible b y this method. When using both methods in DD and EKV, no differences c ompared with the healthy controls could be detected on the volar forea rm, where the skin was principally unaffected; only the measurements f rom the affected skin on alternative sites demonstrated significantly increased TEWL values. In ADI and CI, however, normal-appearing skin a lso showed impaired values. We conclude that both TEWL and the vascula r response to penetration of HN are suitable methods to monitor the sk in barrier function in keratinization disorders, and are helpful in di scriminating between these disorders.