Rai O. Influence of the UV therapy on the level of urocanic acid in the skin in psoriasis

Thesis is devoted to studying of urocanic acid role in the pathogenesis of psoriasis and influence of UV therapy on its level. Significant reduction of urocanic acid activity of enzyme histidase in all patients with psoriasis could be a confirmation of their pathogenic importance. Identification of correlation between the level of urocanic acid and clinical form of psoriasis as well as its type, stage of its course, occurrence and severity of the skin inflammation could be an additional argument of pathogenic relations. We found that urocanic acid protects skin from the sun exposure as a result of decrease of its level when significantly increase dermal photosensitivity. Using spectrophotometric researches was confirmed that UVR increase histidase activity and therefore increase level of urocanic acid in the skin of patients with psoriasis. A new additional diagnostic method considering urocanic acid action was developed and established for the purpose of individual prescription of UVR selective phototherapy or zonal UVR with a quartz lamp and in order to avoid exacerbations. Confirmed that urocanic acid lower 4nmol/sm.kv is unfarorable prognostic factor of exacerbation and could be contindication for the artificial phototherapy.