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

Purpose

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.

Condition	Intervention	Phase
Skin Irritancy Tests	Procedure: 10% lactic acid test Procedure: Placebo	Phase 4

Study Type:	Interventional
Study Design:	Allocation: Randomized Endpoint Classification: Efficacy Study Intervention Model: Parallel Assignment Masking: Double Blind (Subject, Investigator, Outcomes Assessor) Primary Purpose: Diagnostic
Official Title:	Determination of Sensitive Skin in a Mexican Population by Lactic Acid Testing and Its Analysis Through Biophysical Measures

Resource links provided by NLM:

MedlinePlus related topics: Drinking Water

Drug Information available for: Lactic acid Ammonium lactate

U.S. FDA Resources

Further study details as provided by Universidad Autonoma de San Luis Potosí:

Primary Outcome Measures:

Sensitivity to lactic acid [ Time Frame: 10 minutes ] [ Designated as safety issue: No ]
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.

Secondary Outcome Measures:

Erythema [ Time Frame: 0, 3, 5, 8 and 10 minutes ] [ Designated as safety issue: No ]
Measure the presence of erythema through colorimetry (a* axis).
Skin pigmentation [ Time Frame: 0 minutes ] [ Designated as safety issue: No ]
Measure the melanin angle (through L* axis) before performing the test.
Transepidermal water loss [ Time Frame: 0, 3, 5, 8 and 10 minutes ] [ Designated as safety issue: No ]
Quantify the change in TEWL by evaporimetry in grams per squared meter per hour, as an indirect measure of skin barrier disfunction.
Capacitance [ Time Frame: 0, 3, 5, 8, 10 minutes ] [ Designated as safety issue: No ]
Quantify the change in capacitance by corneometry, as an indirect measure of skin barrier disfunction.

Enrollment:	260
Study Start Date:	October 2011
Study Completion Date:	August 2012
Primary Completion Date:	May 2012 (Final data collection date for primary outcome measure)

Arms	Assigned Interventions
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.

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.

Eligibility

Ages Eligible for Study:	18 Years to 70 Years
Genders Eligible for Study:	Both
Accepts Healthy Volunteers:	Yes

Criteria

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

Contacts and Locations

Please refer to this study by its ClinicalTrials.gov identifier: NCT01591993

Locations

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

Sponsors and Collaborators

Universidad Autonoma de San Luis Potosí

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"

More Information

Publications:

Seidenari S, Francomano M, Mantovani L. Baseline biophysical parameters in subjects with sensitive skin. Contact Dermatitis. 1998 Jun;38(6):311-5.

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.

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.

Responsible Party:	Juan Pablo Castanedo Cazares, Dermatology Research Director, Universidad Autonoma de San Luis Potosí
ClinicalTrials.gov Identifier:	NCT01591993 History of Changes
Other Study ID Numbers:	SenSk12
Study First Received:	April 27, 2012
Last Updated:	November 28, 2012
Health Authority:	Mexico: Ministry of Health

Keywords provided by Universidad Autonoma de San Luis Potosí:

Sensitive skin
Lactic acid test
Transepidermal water loss
Colorimetry
Capacitance

ClinicalTrials.gov processed this record on May 23, 2013