Update on pruritic mechanisms of hypertrophic scars in postburn patients: the potential role of opioids and their receptors.

Although itching (or pruritus) in a scar is a very common and distressing symptom and is increasingly being recognized as a significant obstacle in burn rehabilitation, the exact mechanisms underlying this symptom have not been elucidated; hence, a reliable therapy has not been established. Recent findings have suggested that itching caused by inflammatory dermatosis can be reduced by antihistamines, but histamine antagonists cannot block all types of pruritus (eg, neuropathic itch). This indicates the presence of a histamine-independent pathway for itch. Itch or pruritus may also be evoked by direct activation of opioid receptors, which have recently been identified in the skin. This article aims to assess the current state of knowledge regarding the role of opioids in the generation of itch in hypertrophic scars in postburn patients. To this end, the authors have reviewed the relevant literature and present some clinical data. The authors hope that this review will form the basis for future research to elucidate the mechanism and treatment of itch.