Efficacy of topical 10% urea-based lotion in patients with ichthyosis vulgaris: a two-center, randomized, controlled, single-blind, right-vs.-left study in comparison with standard glycerol-based emollient cream

Background: Ichthyoses are genetic disorders of keratinization which are uncomfortable due to their conspicuous scaling, itching and cosmetic problems. Ichthyoses can lead to social discrimination and psychological problems. Ichthyosis vulgaris (IV) is the most common form of these geno-dermatoses. IV is a chronic disorder that often requires continuous therapy. Emollient and keratolytic products are the mainstay treatments of IV. It is important that efficient, safe and well tolerated therapies should be available. Direct comparative data regarding efficacy of different emollient products in IV patients are very few. Objective: The aim of the study was to investigate the keratolytic and moisturizing properties as well as the tolerance of a new urea topical formulation (Ureadin Rx10) when applied to hyperkeratotic and dry skin in patients with (IV) in comparison with a standard emollient cream. Methods: The study was conducted as a two-center, randomized, controlled, single-blind, intra-patient (right-vs.-left) trial design. A total of 30 patients with IV between 8 and 65 (mean age: 25 years) treated with a 10% urea-based lotion, Ureadin Rx 10* (URx), for 4 weeks or a glycerol-based emollient cream, Dexeryl dagger (DC), in a right-vs.-left study design. Primary outcome was a 5-point SRRC Index score (evaluating scaling roughness, redness and cracks) evaluated at baseline and after 2 and 4 weeks of treatment. As secondary endpoints patients evaluated also the global efficacy (GE) and global tolerability (GT) scores with the help of a 10 cm visual analogue scale (0 = no efficacy at all/very bad tolerability; 10: excellent efficacy/excellent tolerability). Results: At baseline the mean (SD) SRRC score was 9.5 (1.9) in the URx treated sites and 9.5 (1.9) in the DC treated sites. A total of 27 patients (90%) concluded the study period. Three patients were withdrawn prematurely because of itching and burning sensation after DC application (1 patient) or URx application (2 patients). At week 4, in comparison with baseline values, both treatments were shown to be clinically effective: SRRC significantly (p = 0.0001) decreased to 3.3 (1.8) after URx (a 65% relative reduction) and to 5.7 (2.5) after DC (a 40% relative reduction). SRRC was significantly lower in URx treated regions in comparison with DC both after 2 and 4 weeks of treatment (p = 0.0005). Mean GE score in areas treated with URx was significantly (p = 0.0001) higher than in the areas treated with the DC (8.9 vs. 7.3). Both treatments were in general well tolerated. GT score was 8.1 (range 10 to 3) with URx and 8.4 (range 10 to 3) with DC application (p = ns). The two main limitations of this trial are the study design (single blind), and the small sample size which is not adequate for an evaluation of safety. Conclusion: Ureadin Rx 10 lotion has shown a greater efficacy on ichthyosis vulgaris in term of reduction of scaling, roughness, redness and cracking in comparison with a glycerol-based emollient cream. Tolerability of the two topical treatments was comparable. Further studies with larger sample sizes are needed for the evaluation of safety and tolerability of urea 10% lotion in this clinical setting.