علاقة الضغط العصبي بالصدفية

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Physiologic Effects of Stress

Normal physiologic response to stress involves activation of the hypothalamus-pituitary-adrenal (HPA) axis and sympathetic adrenomedullary (SAM) axis, both of which interact with immune functions. Generally, in normal individuals, stress elevates stress hormones (i.e., increases cortisol levels). However, according to available studies, exposure to stress in psoriatic patients has been associated with diminished HPA responses and upregulated SAM responses.[14–17] More specifically, when psoriasis sufferers are under such emotional pressures lower plasma cortisol levels14 and higher epinephrine and norepinephrine levels[15] can be induced, when compared with controls.
Similarly, Evers et al.[16] found psoriasis patients had significantly lower cortisol levels at moments when daily stressors are at peak levels. The study also reported that psoriasis patients with overall high levels of daily stressors exhibited lower mean cortisol levels, as compared to psoriatics with overall low levels of daily stressors.[16] Furthermore, Richards et al.[17] observed physiologic differences in response to stress between psoriasis patients who are stress responders and those who are non-stress responders. Specifically, stress-responders had lower salivary and serum cortisol levels than non-stress responders following a social performance stressor.[17]
These blunted HPA axis and elevated SAM system responses to stress may be crucial in better understanding the inflammatory characteristics of psoriasis, particularly in stress-responders. For instance, decreased secretion of cortisol and increased levels of epinephrine and norepinephrine may stimulate the release of mast cells, affect skin barrier function, and upregulate proinflammatory cytokines, which could thereby maintain or exacerbate psoriasis severity.[16] Some authors have commented that this decreased cortisol response may be similar to how psoriasis flares with steroid withdrawal, as evidenced by the well known phenomena of steroid-induced psoriasis reboun