The Effect of Ablation of Epidermal Nerve Fibers Using Capsaicin Cream

The Effect of Ablation of Epidermal Nerve Fibers Using 0.1% Capsaicin Cream on Spontaneous Cutaneous Burning Pain, Tactile Hyperalgesia, and Thermal Hyperalgesia: A Controlled, Masked Trial With an N of 1

This is a study of epidermal (the outer most layer) nerve fibers (ENFs) in the skin of the body; counts of which are used to determine a disease of nerves called "small nerve fiber neuropathy."

Capsaicin is approved by the Food and Drug Administration (FDA) for pain relief. Since 0.1% capsaicin is known to cause ablation (removal) of ENFs, this study will test whether such ablation results in relief of spontaneous pain, touch, or heat-pain.

Study Overview

• Status: Completed
• Conditions: Pain
• Intervention / Treatment: Drug: Capsaicin 0.1%; Drug: Placebo

Detailed Description

On the first day, two areas of the skin of the subject's right abdomen will be marked and identified as sites A and B. Each day for one week the subject will be asked to grade her degree of discomfort or pain from 1 to 10 at sites marked A and B every two hours beginning at 8 a.m. and ending at 10 p.m.

Each day except for Saturday and Sunday touch-pressure sensation will be evaluated using monofilaments and heat pain sensation at sites A and B. Also evaluated will be touch pressure pain at each of these sites.

On Thursday of the first week 3 mm punch biopsies of the skin will be obtained from sites A and B and another 3 mm punch biopsy will be obtained on Thursday of the following week from sites A and B.

Following the first biopsy, the experimental creams will be applied to sites A and B. One of the experimental creams contains 0.1% Capsaisin in a bland cream. The second cream contains no Capsaisin. 0.1% Capsaisin is known to destroy the small fibers, especially pain fibers in the skin. Both the investigators applying the cream and the subject will not know which experimental cream contains the Capsaisin. The creams will be applied on Thursday of the first week but only after all testing and skin biopsies have been done. The creams will be left in place except when testing is being done, and they will not be applied after the second set of skin biopsies has been obtained.

The creams will be applied by the investigators and by the subject, care being taken so that the tube marked A is applied to the site marked A, and the tube marked B is applied to the site marked B. Between application to the two sites, investigators and the subject will use different gloves and applicators, carefully washing their hands with soap and water between and after applications.

The subject will be asked not to shower or to immerse herself in water but to use sponge baths, avoiding the tested areas, so that the cream does not move to other areas.

• Study Type: Interventional
• Enrollment (Actual): 1
• Phase: Phase 1

Contacts and Locations

Study Locations

• United States
  • Minnesota
    • Rochester, Minnesota, United States, 55905
      • Mayo Clinic in Rochester

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 35 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Female

Description

Inclusion Criteria:

• pain syndrome
• must be able to be in study for one week

Exclusion Criteria:

- not able to be in study for one week

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Non-Randomized
• Interventional Model: Factorial Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Capsaicin 0.1%; Capsaicin cream 0.1% will be applied to site A or B on the subject's abdomen daily for 7 days.	Drug: Capsaicin 0.1%; Cream will be cleansed from sites A and B with soap and water each morning before reapplying.; Other Names: Capzacin
Placebo Comparator: Placebo/cream without 0.1% capsaicin; The placebo cream will be applied to site A or B on the subject's abdomen daily for 7 days.	Drug: Placebo; Cream will be cleansed from sites A and B with soap and water each morning before reapplying.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Burning pain as measured by a numeric rating scale of 1-10	1 week

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Tactile hyperalgesia as measured with monofilaments A, B, C, (through I), ranging in providing forces -3, -2, -1 (through +5) In grams	This outcome measure consists of touch pressure testing of tactile hyperalgesia (increased sensitivity to pain) with monofilaments consists of recognizing the lowest level at which the subject can feel the touch of a monofilament hair, and to the point of discomfort or pain. The units for tactile hyperalgesia are In grams of touch pressure.	1 week
Thermal hyperalgesia as measured by the heat as pain thermode test using CASE IVc	This outcome measure tests heat-pain sensation (the lowest degree of a thermal warming pulse that the subject can perceive as discomfort or pain). CASE IVc is a computerized quantitative sensation testing instrument, extensively described. It was originally developed at Mayo Clinic and the Section of Engineering. It is now manufactured by WR Medical Electronics in Maplewood, Minnesota. This instrument provides exponentially increasing pyramidal and trapezoid heat pulses to a maximum of 49 degrees centigrade for 10 seconds.	1 week

Collaborators and Investigators

• Sponsor: Mayo Clinic
• Investigators: Principal Investigator: Peter Dyck, MD, Mayo Clinic

Study record dates

Study Major Dates

• Study Start: June 1, 2013
• Primary Completion (Actual): June 1, 2013
• Study Completion (Actual): June 1, 2013

Study Registration Dates

• First Submitted: June 6, 2013
• First Submitted That Met QC Criteria: June 19, 2013
• First Posted (Estimate): June 21, 2013

Study Record Updates

• Last Update Posted (Estimate): June 21, 2013
• Last Update Submitted That Met QC Criteria: June 19, 2013
• Last Verified: June 1, 2013

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Peripheral Nervous System Agents; Sensory System Agents; Dermatologic Agents; Antipruritics; Capsaicin
• Other Study ID Numbers: 13-002235