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NCT Number: NCT07247695

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

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.

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Key information

Conditions

Itch

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Aalborg University

Gistrup, 9260, Denmark

Location status: Recruiting

Location contact

Silvia Lo Vecchio, PhD

CONTACT

[email protected]

Denmark

CONTACT

Denmark

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Histamine

Other

To deliver histamine, standard allergy skin prick test (SPT) lancets are applied

Cowhage

Other

The spicules will be manually inserted. Approximately 30-35 spicules are gently rubbed into a 1 cm diameter skin area on the forearm/face

Primary outcomes

  1. Measuring pain by computerized Visual Analog Scale Scoring

    Time frame: 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".

  2. Measuring itch by computerized Visual Analog Scale Scoring

    Time frame: 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".

Secondary outcomes

  1. Pain Catastrophizing Scale (PCS).

    Time frame: Baseline

    The PCS assesses negative and exaggerated coping concerning anticipated or experienced painful stimuli. Thirteen items have to be answered on a 5-point Likert-type scale ranging from 0 (Not at all) to 4 (all the time).

  2. Itch Catastrophizing Scale (ICS).

    Time frame: Baseline

    The ICS assesses negative and exaggerated coping concerning anticipated or experienced itchy stimuli. Thirteen items have to be answered on a 5-point Likert-type scale ranging from 0 (Not at all) to 4 (all the time).

  3. Learned Helplessness Scale (LHS)

    Time frame: Baseline

    The questionnaire consists of 20 items, and the participant's response to each item is rated on a 4-point Likert scale ranging from strongly agree (1) to strongly disagree (4).

  4. Depression, Anxiety, Stress Scale (DASS-21)

    Time frame: Baseline

    The questionnaire measures the magnitude of depression, anxiety, and stress. Each of these three subscales consists of 7 questions answered using a 0-3 Likert scale, with 0 meaning "it did not apply to me", and 3 meaning "it applied to me very much"

  5. Reinforcement Sensitivity Theory - Personality Questionnaire (RST-PQ).

    Time frame: Baseline

    The RST-PQ contains in total 65 items must be answered on a Response scale: 4-point Likert (Strongly disagree → Strongly agree).

  6. Positive And Negative Affect Schedule (PANAS)

    Time frame: Baseline

    Twenty words are associated with the subject's current feelings and have to be rated on a 5-points Likert-type scale from: Very slightly or not at all to extremely.

  7. Difficulties in Emotion Regulation Scale Short Form (DERS-SF)

    Time frame: Baseline

    The questionnaire is an 18-item measure used to identify emotional regulation issues in adults. Participants rate each item on a 5-point Likert scale (from 1 to 5).

  8. Emotion Regulation Questionnaire (ERQ

    Time frame: Baseline

    This questionnaire is designed to assess individual differences in the habitual use of two emotion regulation strategies: cognitive reappraisal and expressive suppression. Respondents answer each item on a 7-point Likert-type scale ranging from 1 (strongly disagree) to 7 (strongly agree), where 4 means (neutral).

Study contacts

Contact information is provided by the study sponsor or research team.

Silvia Lo Vecchio

CONTACT

[email protected]

+4521397785

Sponsors and collaborators

Lead sponsor

Aalborg University

Other

Registry information

Official study title

Pain and Itch Neuromodulation: Effects of Offset Analgesia, Placebo, and Nocebo and Topographical Distribution of Itch and Pain Receptors

Important dates

Study start
2025
Primary completion
2026
Study completion
2028
First posted
Nov 25, 2025
Registry last updated
Dec 4, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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