Chronic prurigo (CPG) is a highly burdensome pruritic disease characterized by chronic itch, a prolonged scratching behavior and the development of localized or generalized hyperkeratotic pruriginous lesions. Neuronal sensitization and the development of an itch-scratch cycle contribute to the augmentation of pruritus and the chronicity of the disease. We provide here the first international guideline for a rational diagnostic and therapeutic approach for CPG. Recommendations are based on available evidence and expert opinion. The diagnosis of CPG is made clinically. A detailed medical history together with laboratory and radiological examinations are advised in order to determine the severity of CPG, identify the underlying origin of the itch and assist in the elaboration of a treatment plan. Therapeutically, it is advised to adopt a multimodal approach, including general strategies to control itch, treatment of the underlying pruritic conditions, and of the pruriginous lesions. Topical (corticosteroids, calcineurin inhibitors, capsaicin) and systemic antipruritic agents (eg, gabapentinoids, immunosuppressants, and opioid modulators) as well

All humans experience itch in the course of their life. Even a discussion on the topic of itch or seeing people scratch can evoke the desire to scratch. These events are coined “contagious itch” and are very common. We and others have shown that videos showing people scratching and pictures of affected skin or insects can induce itch in healthy persons and chronic itch patients. In our studies, patients with atopic dermatitis (AD) were more susceptible to visual itch cues than healthy. Also, personality traits like agreeableness and public self-consciousness were associated with induced scratching in skin patients, while neuroticism correlated with induced itch in healthy subjects. The underlying course of contagious itch is not yet fully understood. It is hypothesized that there are human mirror neurons that are active when we imitate actions and/or negative affect. Until now, there has been only limited data on the mechanisms of brain activation in contagious itch though. We have barely begun to understand the underlying physiological reactions and the triggering factors of this phenomenon. We summarize what we currently know about contagious itch and provide some suggestions what future research should focus on.

It is known that itch is associated with psychological variables, but it is not known whether personality characteristics, depression or anxiety are predictors of experimentally induced itch in patients with atopic dermatitis (AD). In this study itch was induced in 27 patients with AD and 28 healthy controls by the presentation of an experimental video on crawling insects and skin diseases. Itch intensity was measured by self-ratings and by observing the number of scratch movements. Itch increase was determined by subtracting itch intensity induced by the experimental video from itch intensity induced by a control video. Psychological variables were assessed using validated questionnaires. In patients with AD, depression was a significant predictor of self-rated induced itch (corrected R2 = 0.175); while agreeableness and public self-consciousness were significant predictors of induced scratching (corrected R2 = 0.534). In healthy controls no associations were found. These results imply that a special group of patients with AD might benefit from certain psychological interventions.

Patients with chronic itch suffer from higher levels of depression and anxiety than their healthy counterparts. Furthermore, psychological factors, such as stress, are known to aggravate itch. The mere act of thinking about itching can induce the sensation. Interventions like habit reversal training and arousal reduction have been shown to have positive effects on itch relief. Yet, there is still limited data on the psychological management to control the itch scratch cycle and a description of methods suitable to address itch. In this review, we describe different psychological interventions shown to be effective in the treatment of chronic itch. We also provide suggestions based on our experience of suitable interventions for patients with different types of itch.