Skin and brain: itch and psychiatric disorders.

Skin diseases (atopic eczema, psoriasis, idiopathic urticaria), systemic diseases (chronic hepatic or renal failure, morbus Hodgkin, diabetes mellitus) and psychiatric disorders (obsessive compulsive disorders, depression, delusions of parasitosis) can occur with itching. The aim of this review is to clarify the link between pruritus and psychiatric morbidity and emphasize the importance of a psychiatric consultation for patients with a chronic itching, without a skin disease. In the last years, there is a growing awareness regarding psychogenic itch, although these types of itch are significantly less studied in comparison to other types of pruritus. Psychogenic pruritus is usually a diagnosis of exclusion. There are not controlled studies about treatment of psychogenic itch, but the same drugs prescribed for neuropathic pain, depression, and anxiety are used. There is a strong association between pruritus and psyche; so, it is important that the dermatologist evaluates psychosomatic dimension. According to the analysis of scientific literature and our clinical experience, pruritus seems to be a rather common phenomenon in patients suffering from depression. Future works should explain the basis of psychopathology of chronic itching thanks to studies of selected groups of patients with a particular type of chronic itching, highlighting the clinical features to establish appropriate and individual targeted care, based on the several types of pruritus. Some questions still unanswered could be clarified in this way. It is really important to decrease the symptoms "itching", because the quality of life of the patient will be improved, but the goal is to identify the underlying mechanisms of itch and establish a targeted therapy, depending on the biological changes and the underlying disease.