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Psoriasis is an inflammatory skin disease associated with an impaired skin barrier. The skin barrier function is dependent on the extracellular lipid matrix which surrounds the corneocytes in the stratum corneum. Ceramides comprise essential components of this matrix. Alterations in the stratum corneum ceramide profile have been directly linked to barrier dysfunction and might be an underlying factor of the barrier impairment in psoriasis. In this study, we investigated the ceramide profile and barrier function in psoriasis. Lesional and non‐lesional skin of 26 patients and 10 healthy controls were analysed using in‐depth ceramide lipidomics by liquid chromatography‐mass spectrometry. Barrier function was assessed by measuring transepidermal water loss. Lesional skin showed a significant decrease in the abundance of total ceramides with significant alterations in the ceramide subclass composition compared to control and non‐lesional skin. Additionally, the percentage of monounsaturated ceramides was significantly increased, and the average ceramide chain length significantly decreased in lesional skin. Altogether, this resulted in a markedly different profile compared to controls for lesional skin, but not for non‐lesional skin. Importantly, the reduced barrier function in lesional psoriasis correlated to alterations in the ceramide profile, highlighting their interdependence. By assessing the parameters 2 weeks apart, we are able to highlight the reproducibility of these findings, which further affirms this connection. To conclude, we show that changes in the ceramide profile and barrier impairment are observed in, and limited to, lesional psoriatic skin. Their direct correlation provides a further mechanistic basis for the concomitantly observed impairment of barrier dysfunction. [ABSTRACT FROM AUTHOR]

Purpose: The present study explored whether people with psoriasis display an attentional bias towards disease‐related threat words and whether this bias occurs relatively early during the phase of stimulus disengagement, or during a later maintained attention phase dominated by controlled strategic processes. We also explored the degree to which attentional bias is dependent on the emotional valence of control words. Methods: Individuals with psoriasis and matched controls took part in 4 online experiments. Participants completed a spatial cueing paradigm using disease‐related threat words and control words as cues, in order to obtain reaction time estimates of attentional bias. Results: We did not observe evidence for attentional bias when control words were matched with threat words for emotional valence, regardless of whether processing time for the cues was limited (Experiment 1: SOA = 250 ms) or extended (Experiment 2: SOA = 1050 ms). We also did not observe evidence for attentional bias when control words of positive valence were used, but processing time was limited (Experiment 3). An attentional bias was only observed (p =.012, Cohen's d =.37) when sufficient processing time was available and positively‐valanced control words were used (Experiment 4). Conclusion: Rather than showing large and generalized AB effects as predicted by previous accounts, our results tentatively suggest that AB in psoriasis is restricted to situations where participants have ample processing time and threat words are easily distinguishable from control words on the basis of emotional valence. The pattern of results suggests that attentional bias in psoriasis is best characterized as a relatively slow strategic process. [ABSTRACT FROM AUTHOR]