Itch and pain

M Schmelz - Neuroscience & Biobehavioral Reviews, 2010 - Elsevier
M Schmelz
Neuroscience & Biobehavioral Reviews, 2010Elsevier
Decades of pain research have succeeded in elucidating complex mechanisms of acute
activation and chronic sensitization of nociceptors leading to pain. In contrast, itch conditions
have received less attention and even basic mechanisms for the induction of itch are still
unclear. In this review we describe itch-specific pathways, but also evidence for a modified
pattern theory of pruritus offering independent mechanisms for the itch induction.
Traditionally pain and itch have been regarded as antagonistic as painful stimuli such as …
Decades of pain research have succeeded in elucidating complex mechanisms of acute activation and chronic sensitization of nociceptors leading to pain. In contrast, itch conditions have received less attention and even basic mechanisms for the induction of itch are still unclear. In this review we describe itch-specific pathways, but also evidence for a modified pattern theory of pruritus offering independent mechanisms for the itch induction. Traditionally pain and itch have been regarded as antagonistic as painful stimuli such as scratching suppress itch and opioids suppress pain, but generate itch. However, concerning mechanisms of sensitization to itch or pain, surprisingly similar patterns have been observed lately in both inflamed tissue and in the spinal cord. These similarities open up two highly interesting perspectives: the role of well established analgesic therapeutic concepts can be validated in chronic itch conditions and on the other hand investigations of sensitization in easily accessible pruritic skin may help to validate concepts of nociception in humans. These perspectives illustrate that itch and pain research no longer follows separate paths, but can be advantageously interconnected.
Elsevier