Chronic pruritus (CP) is a symptom of dermatologic, neurologic, systemic and psychosomatic diseases. CP has a prevalence of ~20% in the general population and is therefore a significant burden on society, but the transition from acute pruritus to CP is not well understood. It probably involves interactions between biological and psychosocial factors and pruritus-specific risk factors as well as mechanisms shared with other persistent somatic symptoms addressed in other projects of the SOMACROSS Research Unit (RU). Here we aim to identify psychosocial and biological factors and their interactions which might be associated with the persistence of CP with and without immunologic/inflammatory origin, that is, atopic dermatitis and pruritus on non-inflamed skin. We expect that psychosocial factors relevant to the persistence of symptoms such as fatigue and pain may also show associations to CP.