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Background. There is evidence that stress and psoriasis interact bidirectionally. Specifically, stress is not only induced by psoriasis, but it is also considered a precipitating factor for onset or exacerbation of the disease. Neuroendocrine alterations of the stress system have been implicated in this association. Objectives. To assess the diurnal rhythm of the hypothalamic-pituitary-adrenal (HPA) axis and hair cortisol levels in patients with psoriasis compared to healthy controls, and further explore whether suggested alterations in HPA axis activity are related to anthropometric, psychological, and disease activity/severity indices. Materials & Methods. We assessed stress levels quantified by questionnaires, psoriasis severity, and stress system activity based on HPA axis biomarkers. The sample comprised 18 adult patients with exacerbation of non-pustular psoriasis compared to 18 healthy controls (18-65 years old). In particular, salivary cortisol diurnal profiles and hair cortisol concentration were evaluated in both groups. Five distinct salivary samples were collected during a day of rest and 3-cm hair segments were cut. Results. A higher prevalence of self-reported anxiety, stress, and depressive symptoms was reported among psoriatic patients compared to healthy controls. Also, blunted salivary cortisol diurnal rhythm in psoriatic patients and a positive correlation of salivary cortisol concentration with state anxiety and psoriasis severity were revealed. No associations were shown between hair cortisol concentrations and disease presence/severity. Conclusion. We provide preliminary evidence that psoriasis patients may demonstrate a hypofunctional HPA axis, while our findings also suggest a complex interaction between HPA axis activity, psychosocial status and pathophysiological processes in psoriasis