Clinical trial NCT01591993: Determination of Sensitive Skin and Its Biophysical Response in a Latin-American Population
Official title: Determination of Sensitive Skin in a Mexican Population by Lactic Acid Testing and Its Analysis Through Biophysical Measures
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE4
Conditions: Skin Irritancy Tests
Keywords: Sensitive skin
Lactic acid test
Transepidermal water loss
Colorimetry
Capacitance
Lead sponsor: Universidad Autonoma de San Luis Potosí
Sponsor class: OTHER
Collaborators: name: Hospital Central "Dr. Ignacio Morones Prieto"
First posted: 2012-05-04
Enrollment: 260
Sex: ALL
Minimum age (years): 18
Maximum age (years): 70
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: DIAGNOSTIC

Brief 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.

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 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

Primary outcomes:
measure: Sensitivity to lactic acid
timeFrame: 10 minutes
Secondary outcomes:
measure: Erythema
timeFrame: 0, 3, 5, 8 and 10 minutes
measure: Skin pigmentation
timeFrame: 0 minutes
measure: Transepidermal water loss
timeFrame: 0, 3, 5, 8 and 10 minutes
measure: Capacitance
timeFrame: 0, 3, 5, 8, 10 minutes
Other outcomes:
Locations:
city: San Luis Potosí
country: Mexico
facility: Dermatology Department. Hospital Central "Dr. Ignacio Morones Prieto"
Study officials:
affiliation: Dermatology Department. Hospital Central "Dr. Ignacio Morones Prieto"
name: Diana V Hernández-Blanco, MD
role: PRINCIPAL_INVESTIGATOR
affiliation: Dermatology Department. Hospital Central "Dr. Ignacio Morones Prieto"
name: Adriana Ehnis-Pérez, MD
role: PRINCIPAL_INVESTIGATOR
affiliation: Dermatology Department. Hospital Central "Dr. Ignacio Morones Prieto"
name: Juan P Castanedo-Cázares, MD
role: STUDY_DIRECTOR
affiliation: Dermatology Department. Hospital Central "Dr. Ignacio Morones Prieto"
name: Bertha Torres-Álvarez, MD
role: STUDY_CHAIR
References:
citation: 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.
citation: 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.
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.