Determination of Sensitive Skin and Its Biophysical Response in a Latin-American Population

Determination of Sensitive Skin in a Mexican Population by Lactic Acid Testing and Its Analysis Through Biophysical Measures

Sensitive skin syndrome is a frequent self-diagnosed entity that has not been previously described in a Latin-american population. One hypothesis to its development is an alteration of the barrier function of the skin. The aim of the study is to describe the frequency of sensitive skin in a mexican population detected through the lactic acid test, and to explore its response through biophysical measures (colorimetry, transepidermal water loss (TEWL) and capacitance). The prevalence of this syndrome in studied populations is approximately 50%. Considering racial skin differences, the investigators would expect at least a 20% prevalence.

For this purpose, the investigators would need a minimum of 243 healthy volunteers, 18 years or older, with previous informed consent, to whom the lactic acid test will be performed. The investigators will record any unpleasant sensation graded in a Visual Analog Scale (VAS) of 10 points, colorimetry, TEWL and capacitance before the test and at 3, 5, 8 and 10 minutes after the lactic acid test.

Study Overview

• Status: Completed
• Conditions: Skin Irritancy Tests
• Intervention / Treatment: Procedure: 10% lactic acid test; Procedure: Placebo

Detailed Description

Sensitive skin is defined as the presence of itching, stinging, burning or other unpleasant sensations due to external factors (such as light, heat, cold, air, cosmetic products, soap, water and even emotional and hormonal factors). By definition it is a subjective syndrome, where there are no clinical signs, making it a self-diagnosed entity. Previous community-based studies, mostly in caucasians, have found a high prevalence in general population. Nonetheless, to date there are only a few studies and with a small amount of subjects that have applied an objective test to identify this syndrome, and even fewer have explored the possible alterations associated to it.

The investigators aim to describe the frequency in a hispanic population, and further explore the presence of alterations in the barrier function through measurement of TEWL and capacitance, as well as possible subclinical erythema (a* axis of colorimetry) or variations due to skin pigmentation (L* axis).

The volunteers in the study will be randomized to receive in one nasolabial fold 10% lactic acid solution, and placebo (0.9% saline solution) in the other to act as the control. The investigators will be grading any unpleasant sensation in a 10-point scale (VAS) at 4 different time intervals: 3, 5, 8 and 10 minutes. The investigators will be measuring colorimetry (ChromaMeter CR-300 (Minolta, Japan)), TEWL (Evaporimeter DermaLab (Cortex Technology, Denmark)) and capacitance (Corneometer DermaLab Moisture Module (Cortex Technology, Denmark)) before performing the test, and at 3, 5, 8 and 10 minutes after it. These time intervals have been previously determined according to previous reports where the maximum intensity of the response is obtained in the first 5 minutes, and after 10 minutes the response gradually diminishes.

Statistical analysis will be performed with square chi test, t-test or U-Mann-Whitney, according to the parametric or non-parametric distribution of the values. All tests will be performed using the JMP software 8.0 (Cary, NC, USA) at 95% of confidence, statistical significance at 5% with 80% power.

• Study Type: Interventional
• Enrollment (Actual): 260
• Phase: Phase 4

Contacts and Locations

Study Locations

• Mexico
  • San Luis Potosí, Mexico, 78210
    • Dermatology Department. Hospital Central "Dr. Ignacio Morones Prieto"

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Healthy volunteers
• Informed consent

Exclusion Criteria:

• Pregnancy
• Known allergy to lactic acid
• Presence of any dermatoses in the nasolabial folds
• Topical o systemic drugs in the previous 4 weeks

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Test subject; To each subject, the investigators will randomly apply 10% lactic acid on one nasolabial fold, once.	Procedure: 10% lactic acid test; To each subject, 10% lactic acid is applied to one nasolabial fold. This will be performed under humidity, temperature and pH control to avoid influence of these variables in the result of the test.
Placebo Comparator: Placebo; To each subject, the investigators will apply placebo (0.9% saline solution) on the contralateral nasolabial fold to the lactic acid, simultaneously.	Procedure: Placebo; To each subject, 0.9% saline solution will be applied to the contralateral nasolabial fold. This will be performed under humidity, temperature and pH control to avoid influence of these variables in the result of the test.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sensitivity to lactic acid	Identify and measure the presence of any unpleasant sensation after the application of 10% lactic acid test to the nasolabial fold. Will serve to identify subjects with sensitive skin.	10 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Erythema	Measure the presence of erythema through colorimetry (a* axis).	0, 3, 5, 8 and 10 minutes
Skin pigmentation	Measure the melanin angle (through L* axis) before performing the test.	0 minutes
Transepidermal water loss	Quantify the change in TEWL by evaporimetry in grams per squared meter per hour, as an indirect measure of skin barrier disfunction.	0, 3, 5, 8 and 10 minutes
Capacitance	Quantify the change in capacitance by corneometry, as an indirect measure of skin barrier disfunction.	0, 3, 5, 8, 10 minutes

Collaborators and Investigators

• Sponsor: Universidad Autonoma de San Luis Potosí
• Collaborators: Hospital Central "Dr. Ignacio Morones Prieto"
• Investigators: Principal Investigator: Diana V Hernández-Blanco, MD, Dermatology Department. Hospital Central "Dr. Ignacio Morones Prieto"; Principal Investigator: Adriana Ehnis-Pérez, MD, Dermatology Department. Hospital Central "Dr. Ignacio Morones Prieto"; Study Director: Juan P Castanedo-Cázares, MD, Dermatology Department. Hospital Central "Dr. Ignacio Morones Prieto"; Study Chair: Bertha Torres-Álvarez, MD, Dermatology Department. Hospital Central "Dr. Ignacio Morones Prieto"

Publications and helpful links

General Publications

• Seidenari S, Francomano M, Mantovani L. Baseline biophysical parameters in subjects with sensitive skin. Contact Dermatitis. 1998 Jun;38(6):311-5. doi: 10.1111/j.1600-0536.1998.tb05764.x.
• Issachar N, Gall Y, Borell MT, Poelman MC. pH measurements during lactic acid stinging test in normal and sensitive skin. Contact Dermatitis. 1997 Mar;36(3):152-5. doi: 10.1111/j.1600-0536.1997.tb00399.x.
• Sparavigna A, Di Pietro A, Setaro M. 'Healthy skin': significance and results of an Italian study on healthy population with particular regard to 'sensitive' skin. Int J Cosmet Sci. 2005 Dec;27(6):327-31. doi: 10.1111/j.1467-2494.2005.00287.x.

Study record dates

Study Major Dates

• Study Start: October 1, 2011
• Primary Completion (Actual): May 1, 2012
• Study Completion (Actual): August 1, 2012

Study Registration Dates

• First Submitted: April 27, 2012
• First Submitted That Met QC Criteria: May 2, 2012
• First Posted (Estimate): May 4, 2012

Study Record Updates

• Last Update Posted (Estimate): November 29, 2012
• Last Update Submitted That Met QC Criteria: November 28, 2012
• Last Verified: November 1, 2012

More Information

Terms related to this study

• Keywords: Sensitive skin; Lactic acid test; Transepidermal water loss; Colorimetry; Capacitance
• Additional Relevant MeSH Terms: Immune System Diseases; Hypersensitivity
• Other Study ID Numbers: SenSk12