Ultrasound assessment of the keratolytic effect of a 50% urea anhydrous paste on psoriasis plaques: A prospective study

BACKGROUND: The keratolytic effect of urea is well-known, although the majority of the available studies rely on clinical observation only. The aim of this open trial was to evaluate, through clinical and ultrasound assessment, the efficacy and tolerability of a 50% urea anhydrous paste on hyperkeratotic psoriatic plaques. METHODS: Twenty-five patients (12 male, 13 female; age: 35-75 years) with plaque psoriasis characterized by an evident hyperkeratotic component were enrolled. One target lesion was selected in each patient that was instructed to apply the 50% urea anhydrous paste twice a day for up to 3-week study duration. RESULTS: Clinical clearance of hyperkeratosis at day 21 was observed in 23 out of 25 plaques (92%), with nine (36%) and ten (40%) patients already reaching clear status respectively at day 7 and 14. Ultrasound significant reduction of the mean epidermal thickness score was also observed at the same time-points. No side effects were reported and all patients rated the product as excellent in terms of cosmetic acceptability. CONCLUSIONS: The tested product resulted to be an effective keratolytic agent in plaque psoriasis. Strength of our study was the ultrasound assessment, allowing to objectively confirm and correlate the epidermal changes seen at clinical evaluation.