Transepidermal water loss in the orphan forms of ichthyosis.

As a surrogate measure of skin barrier dysfunction, we sought to determine differences in transepidermal water loss (TEWL) among ichthyosis subtypes and correlate TEWL with clinical severity. Subjects with Netherton syndrome had the highest TEWL values (increased water loss), while TEWL values were lowest in subjects with epidermolytic ichthyosis. TEWL correlated with severity only in lamellar ichthyosis and age was inversely correlated with TEWL (rs  = -.213, P = .02). TEWL is an objective measure that complements disease severity in ichthyosis and may be used as an adjuvant to monitor treatment response.