Histamine: To deliver histamine, standard allergy skin prick test (SPT) lancets are applied
Cowhage: The spicules will be manually inserted. Approximately 30-35 spicules are gently rubbed into a 1 cm diameter skin area on the forearm/face
Study summary
The study consists of one experimental session of approximately 1½ hours. The participant will fill in a series of questionnaires about how you perceive itch and pain, and about some traits of your personality, such as depression, anxiety and stress. Afterwards, two areas will be selected on each forearm of the subjects. The four areas will be treated with the same vehicle cream for 20 minutes, in order to test the placebo effect. At the end of the cream application, two areas will be randomly treated with histamine while cowhage will be applied on the other two areas. During the 10 minutes of the application of the pruritogens, itch and pain will be continuously monitored using a Visual Analog Scale.
Eligibility
Sex
ALL
Min age
18 Years
Max age
60 Years
Healthy volunteers
Accepted
Inclusion Criteria:
* Healthy men and women
* 18-60 years
* Speak and understand English
Exclusion Criteria:
* Pregnancy or lactation
* Drug addiction defined as any use of cannabis, opioids, or other drugs
* Previous or current history of neurological, immunological, musculoskeletal, cardiac disorder or psychiatric diagnoses 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)
* Contraindications to capsaicin, including intolerance to chili or burns or wounds at the application site
* The subject is assessed as unable to engage in the necessary cooperation required by the study
Primary outcome measure(s)
Measuring pain by computerized Visual Analog Scale Scoring — Immediately after the intervention We will ask the subjects to rate the sensation of pain on a 100 mm Visual Analog Scale ranging from 0 to 100 where 0 indicates" no pain" and 100 indicates "worst pain imaginable".
Measuring itch by computerized Visual Analog Scale Scoring — Immediately after the intervention We will ask the subjects to rate the sensation of itch on a 100 mm Visual Analog Scale ranging from 0 to 100 where 0 indicates "no itch" and 100 indicates "worst itch imaginable".
This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.
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