A comprehensive, tri-national, cross-sectional analysis of characteristics and impact of pruritus in psoriasis.

BACKGROUND: Pruritus is prevalent in psoriasis but still many features of pruritus, its response to therapy and its burden in psoriasis remain to be better characterized. OBJECTIVE: To investigate characteristics and burden of pruritus in an international cohort of patients with psoriasis. METHODS: This cross-sectional study included a total of 634 patients and 246 controls from Germany, Poland and Russia. Physicians examined and interviewed participants, recording clinical characteristics, such as severity, therapy and localization of psoriatic lesions. Participants filled out self-reported questionnaires including questions on pruritus severity and impact, characteristics, and response to therapy, and quality of life (QoL). Localization patterns of pruritus and skin lesions were visualized using body heat maps. RESULTS: Most patients (82%) experienced pruritus throughout their disease, and 75% had current pruritus. The majority of patients (64%) perceived pure pruritus, and those who reported additional painful and/or burning sensations (36%) reported overall stronger pruritus. The scalp was the most frequently reported localization of pruritus, even in the absence of skin lesions. Body surface area (BSA) of pruritus was not linked to pruritus intensity, but to BSA of psoriatic lesions (rho = 0.278; P < 0.001). One third of patients (31%) reported impaired sex-life, and 4% had suicidal ideations due to pruritus. In up to one third of patients, psoriasis therapies had little or no effect on pruritus. The only therapeutic option offered to some of these patients were antihistamines, which appeared to be effective in most cases. CONCLUSION: Pruritus is highly prevalent in psoriasis and is linked to a significant burden. Current psoriasis therapies are frequently insufficient to control pruritus. Managing psoriasis should include the assessment and control of itch. Efficient antipruritic therapies should be developed and be made available for patients with psoriasis.

Common variants of ZNF750, RPTOR and TRAF3IP2 genes and psoriasis risk.

Psoriasis vulgaris is a genetically heterogenous disease with unclear molecular background. We assessed the association of psoriasis and its main clinical phenotypes with common variants of three potential psoriasis susceptibility genes: ZNF750, RPTOR and TRAF31P2. We genotyped 10 common variants in a cohort of 1,034 case-control individuals using Taqman genotyping assays and sequencing. Minor alleles of all four TRAF3IP2 variants were more frequent among cases. The strongest, significant association was observed for rs33980500 (OR = 2.5, p = 0.01790). Minor allele of this SNP was always present in two haplotypes found to be associated with increased psoriasis risk: rs13196377_G + rs13190932_G + rs33980500_T + rs13210247_A (OR = 2.7, p = 0.0054) and rs13196377_A + rs13190932_A + rs33980500_T + rs13210247_G (OR = 1.8, p = 0.0008). Analyses of clinically relevant phenotypes revealed association of rs33980500 with pustular psoriasis (OR = 1.2, p = 0.0109). We observed significant connection of severity of cutaneous disease with variation at rs13190932 and suggestive with three remaining TRAF3IP2 SNPs. Another positive associations were found between age of onset and familial aggregation of disease: smoking and younger age of onset, smoking and occurrence of pustular psoriasis, nail involvement and arthropatic psoriasis, nail involvement and more severe course of psoriasis. We found no statistically significant differences in the prevalence of the examined variants of RPTOR and ZNF750 genes among our cases and controls. We have replicated the association of TRAF3IP2-_rs33980500 variant with the susceptibility to psoriasis. We have found new associations with clinically relevant subphenotypes such as pustular psoriasis or moderate-to-severe cases. We ascertain no connection of RPTOR and ZNF750 variants with psoriasis or its subphenotypes.