Psychological Stress in Patients with Atopic Dermatitis.

Atopic dermatitis (AD) is a frequent dermatosis with a growing incidence and multifactorial and complex pathogenic mechanisms that are still being investigated. Although the connection between AD and psychological stress has been known for a long time, there is a lack of reliable and objective indicators for the characterization of this association. Psychological stress triggers complex immune pathways. Therefore, acute stress quickly triggers a high release of cortisol and adrenalin or noradrenalin which then stimulates the immune system, primarily T-helper type 1 (Th1 cells) to produce pro-inflammatory cytokines, resulting in a cellular immune response and inflammation. On the other hand, chronic stress increases basal cortisol levels and decreases the capacity to mount an acute stress response, with the immune system shifting from a cellular response (which is active in acute stress) to a humoral response. Furthermore, skin keratinocytes contain receptors for neurotransmitters and hormones (muscarinic, adrenergic, glucocorticosteroid, androgenic, estrogenic), thus actively participating in psychoneuroimmunological pathways. The measurement of plasmatic cortisol has been used routinely, but in recent years, particularly in research, preference has been given to measurement of salivary cortisol. Reliable psychological tests are an important additional parameter for assessment of a patient's psychological state. We hope that future studies will supplement our current knowledge on the influence of psychological stress in AD.