Chronic
pruritus of any origin is a frequent discomfort in daily medical practice, and its
therapy is challenging. Frequently, the underlying origin may not be identified and symptomatic
therapy is necessary. Conventional treatment modalities such as
antihistamines often lack efficacy, and hence new therapeutic strategies are necessary. The neuronal mechanisms underlying chronic
pruritus have been partly identified during the past years and offer new therapeutic strategies. For example, mast cell degranulation, activation of neuroreceptors on sensory nerve fibres and
neurogenic inflammation have been identified to be involved in induction and chronification of the symptom. Accordingly, controlling neuroreceptors such as
cannabinoid receptors by agonists or antagonists showed high
antipruritic efficacy.
Pruritus is transmitted to the central nervous system by specialized nerve fibres and sensory receptors. It has been demonstrated that
pruritus and
pain have their own neuronal pathways with broad interactions. Accordingly, classical
analgesics for
neuropathic pain (
gabapentin,
antidepressants) also exhibit
antipruritic efficacy upon clinical use. In summary, these recent developments show that highlighting the basis of
pruritus offers modern neurophysiological and neurochemical therapeutic models and the possibility to treat patients with refractory
itching of different origin.