Objective Evaluation of Skin Sensitivity Across Fitzpatrick Skin Types

July 2020 | Volume 19 | Issue 7 | Original Article | 699 | Copyright © July 2020


Published online June 19, 2020

Celina E. Dubin BA, Grace W. Kimmel MD PhD, Peter W. Hashim MD, John K. Nia MD MPH, Joshua A. Zeichner MD

Icahn School of Medicine at Mount Sinai, New York, NY

Abstract
Context: Skin sensitivity may be best defined as self-reported intolerance to application of skincare products. It is commonly believed that individuals with darker skin are generally less sensitive, while those lighter skin are more sensitive. However, there is little objective data correlating sensitivity with skin type or with objective measures of sensitivity.
Objective: This study assessed Fitzpatrick skin type and self-reported perception of skin sensitivity.
Design: A single-blinded, lactic acid sting test was performed on the medial cheeks, where patients were randomized to receive room temperature 10% lactic acid on the left or right cheek with water applied to the contralateral cheek as a control.
Outcome Measures: Stinging was assessed 1 minute after application of test solution to one cheek using a visual analogue scale (VAS). Results: There was a statistically significant difference in self-reported skin sensitivity in patients with Fitzpatrick skin types 1–3 vs 4–6 (73.6% vs 46.5%; P= 0.006). Patients who had higher perceived sensitivity were more likely to have objectively measured sensitivity as well, across all skin types (P<0.01). When stratified by skin type, a numerically higher percentage of subjects with Fitzpatrick skin types 1–3 experienced objective sensitivity compared to subjects with skin types 4–6 (45.6% vs 27.9; P=0.058).
Conclusions: Patients with self-perceived skin sensitivity were more likely to develop objective stinging compared to those who did not report sensitivity. Skin sensitivity can occur across all skin types, and patients should be asked about self-perceptions of sensitivity as it is likely an indicator of true sensitivity.

J Drugs Dermatol. 2020;19(7): doi:10.36849/JDD.2020.5880

INTRODUCTION

“Sensitive skin” is commonly reported by many patients and influences decision making in skincare routines. Skin sensitivity is generally accepted to be a reduced tolerance to cosmetics and other topical skin care products.1 Based on consumer surveys, it is estimated that 40% of the population believes that they have sensitive skin, and this number appears to be increasing in recent years.1,2 Typically lacking objective signs, skin sensitivity is usually a subjective finding by patients that is secondary to their own perceptions about their skin.3,4 The correlation between perceived sensitivity and objectively sensitive skin has not previously been evaluated. Furthermore, there is limited understanding of which skin types more commonly believe that they have sensitive skin.

The biological basis of skin sensitivity is thought to be the result of many factors. A thin stratum corneum, increased blood flow, and neuronal activation are thought to be major contributing factors.1,3,5 Studies looking at biophysical parameters of the skin reported trends towards increased transepidermal water loss and decreased capacitance in those with sensitive skin, indicating a possible barrier dysfunction.4,6 Fitzpatrick skin type has also been thought to be associated with subjective perceptions of skin sensitivity objective measures.7,8 One study assessing patients with skin responses to irritants found that 85% of affected patients were white.9 Another study found differing symptomatology of skin sensitivity between ethnic groups, showing that Caucasian patients were significantly more likely to report visual effects (eg, redness), whereas African American patients were more likely to report sensory effects (eg, stinging).1 However, other survey studies have shown similar rates of self-reported skin sensitivity across ethnic groups, and therefore the relationship between skin sensitivity and skin type remains unclear.10,11 There is data to suggest that there are biophysical differences in the skin among skin types, and the skin of African American individuals has a thicker stratum corneum and increased lipid content.11,12 Since there is limited research on the relationship between perceived skin sensitivity and skin type, it is unclear whether Fitzpatrick skin type truly plays a role in determining overall sensitivity.

A sting test using lactic acid solution (5% or 10%) is an effective way to create a non-damaging reaction on the face and is been widely accepted as a marker of skin sensitivity.4 Previous studies have shown significantly higher stinging scores in response to lactic acid in patients with sensitive skin, and that