Chronic pruritus – pathogenesis, clinical aspects and treatment

Abstract Chronic pruritus is a major symptom in numerous dermatological and systemic diseases. Similar to chronic pain, chronic pruritus can have a dramatic impact on the quality of life and can worsen the general condition of the patient considerably. The pathogenesis of itch is diverse and involves a complex network of cutaneous and neuronal cells. In recent years, more and more itch‐specific mediators and receptors, such as interleukin‐31, gastrin‐releasing peptide receptor or histamine H4 receptor have been identified and the concept of itch‐specific neurons has been further characterized. Understanding of the basic principles is important for development of target‐specific treatment of patients with chronic pruritus. In this review, we summarize the current knowledge about the pathophysiological principles of itch and provide an overview about current and future treatment options. Key points Chronic pruritus is a common problem affecting a large proportion of the population. The pathophysiological mechanisms underlying chronic pruritus are still insufficiently understood. In the skin, diverse and complex interactions of keratinocytes, mast cells and sensory nerves largely determine the occurrence and the control of pruritus. Management of patients with chronic pruritus requires an individually tailored therapy based on the condition of the skin (inflamed or non‐inflamed), possible underlying causes and existing co‐medication. Systemic treatment with antihistamines often requires up‐dosing up to 4‐fold of the recommended daily dose. Alternative systemic treatments of chronic pruritus are anticonvulsant drugs, μ‐opioid receptor antagonists, antidepressants and UV light therapy. Novel treatment options for chronic pruritus are to be expected in the near future and include H4 receptor antagonists, κ‐opioid receptor agonists and neurokinin 1‐receptor antagonists.