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NCT Number: NCT04076865

Evaluation of the Effect Induced by Repeated Administration of Topical Local Anaesthetic (EMLA) on Itch

In this experiment, the investigators would like to study if the repeated application of local cuaneous anaesthetic EMLA cream will reduce itch induced by small needles from the plant mucuna pruriens (also known as cowhage) and histamine (an itch proving substance formed in the body).

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Key information

Conditions

Lidocaine Itch Pathological Conditions, Signs and Symptoms Pruritus Signs and Symptoms Skin Diseases Skin Manifestations Skin and Connective Tissue Diseases

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Aalborg University

Aalborg, North Denmark, 92200, 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 neurologic, musculoskeletal or mental illnesses
  • Lack of ability to cooperate
  • Current use of medications that may affect the trial
  • Skin diseases
  • Consumption of alcohol or painkillers 24 hours before the study days and between these
  • Acute or chronic pain
  • Participation in other trials within 1 week of study entry (4 weeks in the case of pharmaceutical trials)
  • Known history of anaphylactic shock, or local allergy (contact dermatitis) to lidocaine, prilocaine or other local anaesthetics of the amide type.

Treatment and study plan

EMLA (lidocaine) +Itch (Histamine and cowhage)

Drug

Cutaneous anaesthesia: will be topically induced by using EMLA cream 5%, a local anaesthetic cream consisting of equal parts of lidocaine and prilocaine (1g contains 25 mg of lidocaine and 25 mg of prilocaine, AstraZeneca A/S, Albertslund, Denmark).

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

Cowhage: Cowhage spicules are 1-2 mm in length and have diameter of 1-3 um at their tip, once inserted into the epidermis, the spicules evoke a moderate sensation of itch and to a lesser extent sensations of burning and stinging pain.

Primary outcomes

  1. Superficial blood perfusion

    Time frame: Change from baseline, up to three days after the first session

    is measured by a Speckle contrast imager (FLPI, Moor Instruments, England).

  2. Warm Detection Thresholds and Heat Pain Thresholds

    Time frame: Change from baseline, up to three days after the first session

    The tests for thermal sensation will all be performed using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device

  3. Pain to Supra-threshold Heat Stimuli

    Time frame: Change from baseline, up to three days after the first session

    The tests for thermal sensation will all be performed using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device

  4. Alloknesis

    Time frame: Change from baseline, up to three days after the first session

    Alloknesis is measured by using mildly pruritic, non-painful von Frey nylon filaments of a predetermined intensity (generally 5-30 miliNewton of force).

  5. Mechanical Pain Thresholds and Sensitivity

    Time frame: Change from baseline, up to three days after the first session

    This test is performed using a pin-prick set (Aalborg University, Aalborg). The set consists of 8 needles each having a diameter of 0.6 mm and different force applications: 0.8, 1.6, 3.2, 6.4, 12.8, 25.6, 50.1 and 60.0 g

  6. Pain rating

    Time frame: only on day 3 (third session)

    The subject will rate the pain for 9 min by using a a visual analog scale (VAS) on a tablet. This scale goes from 0 to 100. 0 indicates 'no pain' and 100 indicates 'worst imaginable pain'.

Secondary outcomes

  1. Itch rating

    Time frame: only on day 3 (third session)

    The subject will rate the itch for 9 min by using a a visual analog scale (VAS) on a tablet. This scale goes from 0 to 100. 0 indicates 'no itch' and 100 indicated 'worst imaginable itch'.

Sponsors and collaborators

Lead sponsor

Aalborg University

Other

Registry information

Official study title

A Mechanistic Evaluation of the Nociceptive Desensitization Induced by Repeated Administration of Topical Local Anaesthetic Mixture of Lidocaine and Prilocaine (EMLA) in a Model of Histaminergic and Non-histaminergic Itch.

Important dates

Study start
2019
Primary completion
2020
Study completion
2021
First posted
Sep 3, 2019
Registry last updated
Jan 15, 2021

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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