Ultrasonographic Assessment of the Local Cutaneous Changes Induced by Phototherapy in Psoriasis Patients

Abstract

High-frequency ultrasonography can be used for the detection of cutaneous changes associated with phototherapy. The aim of the study was to assess the changes of ultrasonographic (US) parameters in psoriasis patients, exposed to UV-rays. The study was performed on 20 psoriasis subjects, that underwent a variable number of phototherapy sessions. The cutaneous changes were assessed with a 20-MHz ultrasound scanner (Dermascan C, Denmark). US images were acquired from dorsal forearm (DF) and zygomatic level (ZL), before and after phototherapy. The following parameters were measured: thickness of epidermis and dermis and the number of low, medium and high echogenic pixels. After phototherapy we noticed a decrease of the epidermal thickness at DF (0.173 ± 0.038 mm vs 0.183 ± 0.024, p = 0.03) and ZL (0.148 ± 0.028 mm vs 0.157 ± 0.032, p = 0.025); an increase of the dermis thickness on the DF (1.093 ± 0.389 mm vs 0.095 ± 0.269, p = 0.03) and ZL (1.599 ± 0.263 vs 1.399 ± 0.332, p = 0.02); an increase of low (DF: 9631.88 ± 3771.24 vs 1066.33 ± 2739.28, ZL: 1999.1 ± 5254.33 vs 17801.86 ± 532.45) and medium echogenic pixels (DF: 1937.77 ± 1445.31 vs 1654 ± 763,76, ZA: 1089.71 ± 1057.95 vs 987.11 ± 951,52 vs) on both examined sites and a significant decrease of hyperechogenic pixels on the DF (1169.55 ± 1067.53 vs 673.77 ± 580.36, p = 0.006). High frequency ultrasonography is a modern, noninvasive method that offers specific and objective markers that quantify local cutaneous changes induced by phototherapy.