## 3 Results
### Relationship between Pruritus and Sleep Disturbance  
The sleeping problems reported were linked with pruritus intensity. Patients who had more severe pruritus measured with 10-PSS, NRSmax, and NRSaverage more commonly reported difficulties in falling asleep, awakenings from sleep and the need to use sleeping pills (Table 4). All differences between compared groups were significant (\(p<0.001\) for all comparisons in-between the subgroups).  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & \multicolumn{3}{c}{**DLQI**} \\ \cline{2-4}  & \(n\) & \multicolumn{1}{c}{**Spearman Rank Correlation**} & \\  & & **Coefficient (\(p\))** & \(p\) \\ \hline
**PASI** & 209 & 0.41 & \textless{}0.001 \\ \hline
**BSA** & 281 & 0.38 & \textless{}0.001 \\ \hline
**sPGA** & 293 & 0.37 & \textless{}0.001 \\ \hline
**GPPSI** & 23 & 0.34 & 0.12 \\ \hline
**PPSI** & 42 & 0.52 & \textless{}0.001 \\ \hline
**NRS\({}_{\text{max}}\)** & 274 & 0.39 & \textless{}0.001 \\ \hline
**NRS\({}_{\text{average}}\)** & 274 & 0.34 & \textless{}0.001 \\ \hline
**10-PSS** & 263 & 0.51 & \textless{}0.001 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Correlations between Dermatology Life Quality Index (DLQI) and indices of psoriasis severity and pruritus intensity according to Spearman rank correlation test (10-PSS—10-item Pruritus Severity Scale, BSA—Body Surface Area, GPPSI—Generalized Pustular Soriasis Severity Index, NRSaverage—average Numerical Rating Scale, NRSmax—maximal Numerical Rating Scale, PASI—Psoriasis Area and Severity Index, PPSI—Palmoplantar Pustulosis Severity Index, sPGA—static Physician Global Assessment).  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & & \(n\) & \multicolumn{1}{c}{**Mean DLQI**} & \(p\) \\ \cline{3-5}  & Almost always & 67 & 17.3 \(\pm\) 7.1 & \\ \cline{2-5} Problems in falling asleep & Rarely & 115 & 13.5 \(\pm\) 7.0 & \textless{}0.001 \\ \cline{2-5}  & Never & 111 & 9.0 \(\pm\) 7.5 & \\ \hline \multirow{3}{*}{\
\begin{tabular}{c} Awakenings \\ during the night \\ \end{tabular} } & Almost every night & 60 & 17.4 \(\pm\) 7.0 & \\ \cline{2-5}  & Rarely & 98 & 13.9 \(\pm\) 7.5 & \textless{}0.001 \\ \cline{2-5}  & Never & 135 & 9.7 \(\pm\) 7.2 & \\ \hline \multirow{3}{*}{
\begin{tabular}{c} Use of sleeping \\ medication \\ \end{tabular} } & Almost every day & 10 & 18.4 \(\pm\) 7.0 & \\ \cline{2-5}  & Rarely & 51 & 15.5 \(\pm\) 7.0 & \textless{}0.001 \\ \cline{2-5}  & Never & 232 & 11.8 \(\pm\) 7.9 & \\ \hline \hline \end{tabular}
\end{table}
Table 3: Comparison of quality of life in relation to the sleeping problems (DLQI—Dermatology Life Quality Index).  
Correlation between Severity of Pruritus and Quality of Life and Sleep Disturbances in Different Clinical Subtypes of Psoriasis  
The intensity of pruritus was correlated with impairment of the QoL and the QoL impairment in patients with psoriasis of the scalp and palmoplantar pustular psoriasisis. Surprisingly, QoL of patients suffering from erythroderric and small-plaque psoriasis did not depend on the severity of itching (Table 5).  
The clinical subtype of psoriasis was not related to difficulties with falling asleep (\(p=0.83\)), awakenings during the night (\(p=0.84\)), or the need to use the sleeping pills (\(p=0.34\)).