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

Skin Irritancy Tests Clinical Trial

Official title:

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01591993
• Other study ID #: SenSk12
• Status: Completed
• Phase: Phase 4
• First received: April 27, 2012
• Last updated: November 28, 2012
• Start date: October 2011
• Est. completion date: August 2012

Study information

• Verified date: November 2012
• Source: Universidad Autonoma de San Luis Potosí
• Contact: n/a
• Is FDA regulated: No
• Health authority: Mexico: Ministry of Health
• Study type: Interventional

Clinical Trial Summary

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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 260
• Est. completion date: August 2012
• Est. primary completion date: May 2012
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 18 Years to 70 Years

Eligibility

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 Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Investigator, Outcomes Assessor), Primary Purpose: Diagnostic

Related Conditions & MeSH terms

• Skin Irritancy Tests

Intervention

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
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.

Locations

Country	Name	City	State
Mexico	Dermatology Department. Hospital Central "Dr. Ignacio Morones Prieto"	San Luis Potosí

Sponsors (2)

Lead Sponsor	Collaborator
Universidad Autonoma de San Luis Potosí	Hospital Central "Dr. Ignacio Morones Prieto"

Country where clinical trial is conducted

Mexico, 

References & Publications (3)

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. — View Citation

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

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. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	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	No
Secondary	Erythema	Measure the presence of erythema through colorimetry (a* axis).	0, 3, 5, 8 and 10 minutes	No
Secondary	Skin pigmentation	Measure the melanin angle (through L* axis) before performing the test.	0 minutes	No
Secondary	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	No
Secondary	Capacitance	Quantify the change in capacitance by corneometry, as an indirect measure of skin barrier disfunction.	0, 3, 5, 8, 10 minutes	No