Mechanisms Underlying the Placebo Effect in Both Histaminergic and Non-histaminergic Itch

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