Power Doppler Sonography assessment of Psoriatic patients treated with Narrowband-UVB

Abstract

Psoriasis is a common, genetically determined, relapsing inflammatory disease of the skin, which may be triggered by environmental stimuli such as physical trauma, stress, certain drugs, endocrinal and climatic factors. Plaque psoriasis is clinically characterized by sharply demarcated erythematous plaque covered with silvery white scales, which can occur at any site but usually it affects elbows and knees in a symmetric fashion. Histologically, psoriatic epidermis is characterized by parakeratosis, elongated rete ridges, munro microabscess and spongiform pustules of Kogoj. The dermis shows dilated and elongated superficial capillaries passing into the dermal papillae with multiple vascular segments in the papillary tip. Narrowband-ultraviolet B has become one of the most commonly used modalities for the treatment of a variety of skin diseases. NB-UVB has immunosuppressive properties and is used in the treatment of many autoimmune diseases as psoriasis and vitiligo. Ultrasounds with varying frequencies were used earlier to detect morphological changes in various inflammatory diseases (e.g. scleroderma ). The advancement in the field of ultrasound allows the use of Doppler ultrasound in the detection of blood flow in various soft tissues. This work was performed to compare the findings of PDS with clinical and histological findings before and after treatment with NB-UVB. The study included 20 patients of psoriasis vulgaris (16 males and 4 females), their ages ranged from 20 to 60 years and 20 healthy persons served as control group. Patients were treated with NB-UVB with 70% of the minimal erythema dose (MED) and increment of 20% was given if no erythema was induced and 10% if there was slight erythema. Sessions were given three times weekly, 48 hours apart for 10 weeks. Power Doppler Sonography examination of psoriatic plaques and the perilesional normal skin was done for all patients and the results were compared to skin biopsies of the same psoriatic plaques examined by PDS. Skin biopsies were stained with CD34 stain (immunohistochemistry) to have more detailed information about blood vessels. Power Doppler sonography examination, skin biopsies and PASI score were performed before the start of NB-UVB treatment and after 10 weeks of treatment. Using an image-analyzer, area of blood vessels stained with CD34 was calculated together with the area percentage of CD34 stain. PDS examination was also done for 20 healthy controls matching sites with patients. The obtained data was tabulated and subjected to statistical analysis. The results of our study showed a highly significant reduction in PASI, PDS score, area of blood vessels and CD34 area percentage in patients after treatment. There was also a highly significant difference in PDS score between patients before treatment and controls. There was no significant correlation between PDS score and PASI score before treatment, while there was a highly significant direct correlation between PDS score and each of area of blood vessels and CD34 area percentage.