Regional Differences of Cutaneous Irritation and Its Effect on Skin Barrier Recovery

Study Overview
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Brief Summary
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Irritant contact dermatitis induced by sodium lauryl sulphate (SLS) is often used as a model for testing efficacy of various topical preparations. Aforementioned model is standardized and described in guidelines, but it is not explicitly stated where the irritation should be induced. Published clinical trials usually irritate volar aspect of forearms or upper back. Also, lower back and dorsal aspect of forearm are sometimes used. Skin parameters vary depending on anatomic location of measured skin. There is a difference in stratum corneum thickness, hydration and transepidermal water loss across different locations, including between volar forearm and upper back. Furthermore, regional difference in skin response to irritation by tape stripping and benzalkonium chloride were observed. Such differences are also possible in SLS irritation model. One study has shown higher, but not statistically significant, response of back in comparison to forearms, but it had a very small sample size (n=9). Moreover, there are regional variations of topical preparations absorption. Hydrocortisone had 1,7 times higher absorption when applied to upper back in comparison to forearms. Those variations could be explained by different corneocyte size and number of their layers between back and hands. Skin baseline properties and response to irritation seem to be dependent on anatomic position. Those differences could mean different response to treatment. Since published trials only tested efficacy of various preparations on one anatomic location, it is possible their results would be different if tested on other body parts. It could limit validity and usefulness of conducted trials. The aim of this study is to determine if there are regional differences of skin response to irritation and emollient cream treatment in irritant contact dermatitis model.

Official Title
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Regional Differences of Cutaneous Irritation and Its Effect on Skin Barrier Recovery: A Randomised, Controlled Trial

Conditions
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Irritant Contact Dermatitis

Intervention / Treatment
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* Procedure: Sodium lauryl sulphate induced irritation
* Other: Emollient, moisturizing cream


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: young, healthy volunteers who gave written informed consent Exclusion Criteria: skin disease, skin damage on measurement sites, use of corticosteroids and immunomodulators a month prior the inclusion and during the trial, use of emollients three days prior the inclusion in the trial, non-adherence to the trial protocol, exposure to artificial UV radiation, pregnancy and lactation

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: SLS irritation model and Treatment<br>SLS induced irritation on two sites each on forearms and back Emollient cream treatment | Procedure: Sodium lauryl sulphate induced irritation<br>* Sodium lauryl sulphate will be applied to specified skin sites according to randomization protocol to induce irritation. 60 uL of 2% w/v SLS will be applied to skin under occlusion by large Finn chamber for 24 hours as described in the guidelines by Standardization group of European Society of Contact Dermatitis.<br>Other: Emollient, moisturizing cream<br>* Commercially available topical emollient cream will be applied by each participant to treatment sites according to randomization protocol.<br>|
| Placebo Comparator: SLS irritation model and No Treatment<br>SLS induced irritation on two sites each on forearms and back No treatment | Procedure: Sodium lauryl sulphate induced irritation<br>* Sodium lauryl sulphate will be applied to specified skin sites according to randomization protocol to induce irritation. 60 uL of 2% w/v SLS will be applied to skin under occlusion by large Finn chamber for 24 hours as described in the guidelines by Standardization group of European Society of Contact Dermatitis.<br>|
| Sham Comparator: Sham irritation and Treatment<br>Sham irritation (water) on two sites each on forearms and back Emollient cream treatment | Other: Emollient, moisturizing cream<br>* Commercially available topical emollient cream will be applied by each participant to treatment sites according to randomization protocol.<br>|
| No Intervention: Sham irritation and No Treatment<br>Sham irritation (water) on two sites each on forearms and back No treatment | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Transepidermal water loss | Tewameter will be used to assess skin barrier function as a measurement of the water loss (g/hm2). | Five measurements; baseline, irritation, first, third and ninth day of treatment | 
| Stratum corneum hydration | Corneometer will be used to estimate skin dryness. It is a relative measurement and uses arbitrary units (AU). | Five measurements; baseline, irritation, first, third and ninth day of treatment | 
| Erythema | Mexameter will be used to assess erythema. It is a relative measurement and uses arbitrary units (AU). | Five measurements; baseline, irritation, first, third and ninth day of treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Clinical score | Skin response to irritation and treatment will be assessed using a five-point scale to describe changes in skin erythema, roughness, scaling, oedema, and fissures. | Five assessments: baseline, irritation, first, third and ninth day of treatment | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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irritant contact dermatitis, sodium lauryl sulphate, emollients, transepidermal water loss