investigation of the effects of sleep deprivation on itch and pain sensitivity

Conditions: Histamine; Cowhage; Sleep Deprivation

Summary: in this experiment, the investigators would like to test following hypotheses regarding the influence of sleep deprivation on itch: * to investigate similarity and differences between itch and pain by comparing the effect of sleep deprivation in them. * to evaluate the inflammatory state induced by sleep fragmentation via the analysis of c-reactive protein (crp) levels from blood samples. * to correlate the anxiety and depression scores (evaluated through questionnaires) with itch and pain sensitivity and evaluate how they are affected by sleep. in this experiment, the investigators would like to test following hypotheses regarding the influence of sleep fragmentation on itch: * to investigate similarity and differences between itch and pain by comparing the effect of sleep deprivation in them. * to evaluate the inflammatory state induced by sleep fragmentation via the analysis of c-reactive protein (crp) levels from blood samples. * to correlate the anxiety and depression scores (evaluated through questionnaires) with itch and pain sensitivity and evaluate how they are affected by sleep deprivation.

chronic itch affects approximately a fifth of the global population and is associated with substantial negative consequences for the affected individuals. furthermore, there is a lack of efficient treatment options for chronic itch. poor sleep is a common companion of itch and is often reported by patients with chronic itch. poor sleep is often characterized by nightly awakenings and troubles falling asleep. this is a significant problem as poor sleep in general is associated with lowered quality of life. while previous research has already established the negative impact of itch on sleep, it is yet to be studied whether the opposite tendency might be true as well. knowledge about patients with chronic pain has shown that poor sleep can increase the sensitivity to pain and inflammation, and this tendency can also be observed in healthy participants after experimental sleep provocations. therefore, the investigators wish to investigate how sleep provocations affect markers of itch in healthy participants.

Eligibility criteria:
inclusion criteria: * healthy men and women * 18-60 years * speak and understand english * access to a smartphone during the experimental nights exclusion criteria: * pregnancy or lactation * drug addiction defined as any use of cannabis, opioids, or other drugs * previous or current history of neurological, dermatological, immunological musculoskeletal, cardiac disorder or mental illnesses (psychiatric diagnosis) that may affect the results (e.g., neuropathy, muscular pain in the upper extremities, anxiety, depression, schizophrenia etc.) * moles, wounds, scars, or tattoos in the area to be treated or tested * current use of medications that may affect the trial such as antihistamines and pain killers. * skin diseases * consumption of alcohol or painkillers 24 hours before the study days and between these * acute or chronic pain and itch * participation in other trials within 1 week of study entry (4 weeks in the case of pharmaceutical studies) * lack of ability to cooperate