Atopic dermatitis and psychological stress

Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disease. Its main features are eczematous skin lesions with a typical distribution and severe pruritus. Allergens, skin irritants, systemic or local infections, environmental pollutants and hormonal changes have a role in the pathophysiology of AD. A further important trigger factor for both intrinsic and extrinsic AD is emotional stress. Recently published observations point to direct psychoneuroimmunological and -endo-crinological mechanisms: Psychological stress causes a transient increase of peripheral blood eosinophil count and an increase in both CD8+/CD11b+ and CLA+ T-cells. In addition, stress changes the cytokine and the hormone profile with increased levels of IFN-gamma and IL-5, and decreased levels of cortisol in AD patients in contrast to healthy controls. These findings underline the role of immunological changes and a possible suppressed hypothalamic-pituitary-adrenal (HPA) axis closing the loop for the final aggravation of AD.