DERMATOLOGY: CLINICAL & BASIC SCIENCE SERIES SENSITIVE SKIN SYNDROME pdf

DERMATOLOGY: CLINICAL & BASIC SCIENCE SERIES
SENSITIVE SKIN
SYNDROME
Published Titles:
Bioengineering of the Skin: Cutaneous Blood Flow and Erythema
Enzo Berardesca, Peter Elsner, and Howard I. Maibach
Bioengineering of the Skin: Methods and Instrumentation
Enzo Berardesca, Peter Elsner, Klaus P. Wilhelm, and Howard I. Maibach
Bioengineering of the Skin: Skin Biomechanics
Peter Elsner, Enzo Berardesca, Klaus-P. Wilhelm, and Howard I. Maibach
Bioengineering of the Skin: Skin Surface, Imaging, and Analysis
Klaus P. Wilhelm, Peter Elsner, Enzo Berardesca, and Howard I. Maibach
Bioengineering of the Skin: Water and the Stratum Corneum,
Second Edition
Joachim W. Fluhr, Peter Elsner, Enzo Berardesca, and Howard I. Maibach
Contact Urticaria Syndrome
Smita Amin, Arto Lahti, and Howard I. Maibach
Cutaneous T-Cell Lymphoma: Mycosis Fungoides and Sezary Syndrome
Herschel S. Zackheim and Howard I. Maibach
Dermatologic Botany
Javier Avalos and Howard I. Maibach
Dermatologic Research Techniques
Howard I. Maibach
Dry Skin and Moisturizers: Chemistry and Function, Second Edition
Marie Lodén and Howard I. Maibach
The Epidermis in Wound Healing
David T. Rovee and Howard I. Maibach
Hand Eczema, Second Edition
Torkil Menné and Howard I. Maibach
Human Papillomavirus Infections in Dermatovenereology

Gerd Gross and Geo von Krogh
The Irritant Contact Dermatitis Syndrome
Pieter van der Valk, Pieter Coenrads, and Howard I. Maibach
Latex Intolerance: Basic Science, Epidemiology, and Clinical
Management
Mahbub M. V. Chowdhry and Howard I. Maibach
DERMATOLOGY: CLINICAL & BASIC SCIENCE SERIES
Series Editor Howard I. Maibach, M.D.
Nickel and the Skin: Absorption, Immunology, Epidemiology,
and Metallurgy
Jurij J. Host
´
yneck and Howard I. Maibach
Pesticide Dermatoses
Homero Penagos, Michael O’Malley, and Howard I. Maibach
Protective Gloves for Occupational Use, Second Edition
Anders Boman, Tuula Estlander, Jan E. Wahlberg, and Howard I. Maibach
Sensitive Skin Syndrome
Enzo Berardesca, Joachim W. Fluhr, and Howard I. Maibach
Skin Cancer: Mechanisms and Human Relevance
Hasan Mukhtar
Skin Reactions to Drugs
Kirsti Kauppinen, Kristiina Alanko, Matti Hannuksela, and Howard I. Maibach

DERMATOLOGY: CLINICAL & BASIC SCIENCE SERIES
SENSITIVE SKIN
SYNDROME
Edited by
Enzo Berardesca
San Gallicano Dermatological Institute

Rome, Italy
Joachim W. Fluhr
Friedrich-Schiller University
Jena, Germany
Howard I. Maibach
University of California
San Francisco, California, U.S.A.
New York London
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Preface
Sensitive skin is becoming a common clinical condition that dermatologists should
be prepared to recognize, understand, and treat.
Subjects experiencing this condition report exaggerated reactions when
their skin is in contact with cosmetics, soaps, and other substances, and they
often report worsening after exposure to dry and cold climates. Sensitive skin
and subjective irritation are widespread in western countries, but still far from
being completely defined and understood. The development in these recent
years of cosmetic sciences and in particular of cosmetic dermatology has pro-
vided solutions and answers to many needs of the dermatological patient with
cosmetic problems; nevertheless, the management of sensitive skin is still a dif-
ficult task where the rate of patient dissatisfaction is tremendously high.
We hope with this book to give a deep overview on the main physiological
basis of skin reactivity as well as on the many mechanisms which may generate
this condition that to our understanding should be referred to as “sensitive skin
syndrome.”
Enzo Berardesca
Joachim W. Fluhr
Howard I. Maibach

iii

Contents
Preface . . . . iii
Contributors . . . . xi
1. What Is Sensitive Skin? . . . . . 1
Enzo Berardesca, Joachim W. Fluhr, and Howard I. Maibach
Epidemiology 2
Clinical Parameters . . . . 4
Conclusions . . . . 4
References . . . . 5
2. The Somatosensory System . . . 7
Francis McGlone and David Reilly
Somatosensation . . . . 7
The Peripheral Nervous System . . . . 8
The Central Projections . . . . 21
References . . . . 25
3. Neurophysiology of Itch . . . . . 31
Martin Schmelz
Neurophysiology of Itch . . . . 31
Specialized “Itch Neurons” 31
Pruritic Mediators . . . . 33
Sensitization for Itch 36
Experimental Models for Itch . . . . 39
References . . . . 40
v
4. Ethnic Sensitive Skin 47
Manisha J. Patel and Gil Yosipovitch
Biophysical Parameters 48
Skin Irritation . . . . 49

Nerve Fiber . . . . 50
References . . . . 51
5. Ethnic Differences in Skin Sensitivity and Responses
to Topically Applied Products . 53
Enzo Berardesca and Howard I. Maibach
Skin Permeability . . . . 53
Biophysical Parameters 54
Skin Disease and Cosmetic Problems 55
Effects of Topically Applied Products . . . . 56
Effects of Bleaching Agents and Exogenous
Ochronosis . . . . 57
References . . . . 58
6. The Complex Problems of Sensitive Skin 61
Marie C. Marriott, David A. Basketter, and Karen J. Cooper
Introduction . . . . 61
Reactivity to Different Sensory Irritants . . . . 62
Objective Irritation . . . . 63
Relationship Between Sensory and
Objective Irritation . . . . 63
References . . . . 64
7. Surface Stripping Techniques and Sensitive Skin . . 67
Marc Paye and Ge
´
rald E. Pie
´
rard
Introduction . . . . 67
Skin Surface Stripping Techniques . . . . 68
Skin Barrier Function, Sensitivity, and Squamometry 69
Skin Barrier Function, Sensitivity, and

Corneocyte Size . . . . 70
Atopic Dermatitis and Corneosurfametry . . . . 70
Corneosurfametry to Differentiate Between Different
Types of Sensitive Skin . . . . 70
Use of Squamometry to Select Surfactant-Based Products
for Sensitive Skin Subjects . . . . 71
Use of Skin Surface Stripping Methods for Testing Barrier
Protectants for Sensitive Skin Subjects . . . . 71
Conclusion 72
References . . . . 72
vi Contents
8. Technical Bases of Biophysical Instruments Used in
Sensitive Skin Testing 75
Maria Breternitz, Joachim W. Fluhr, and Enzo Berardesca
Introduction: What Is Sensitive Skin? 75
Assessment with Non-Invasive Biophysical Instruments . . . . 80
Summary . . . . 100
Names and Addresses of Mentioned Products . . . . 101
References . . . . 102
9. Identification of a Sensitive Skin Panel . . 107
Marie C. Marriott, David A. Basketter, Karen J. Cooper, and
Lisa Peters
Introduction . . . . 107
Definition of Sensitive Skin 108
Test Methods for Investigating Sensitive Skin 110
Problems Associated with Identifying a Sensitive Skin Panel . . . . 113
Conclusions . . . . 117
References . . . . 117
10. Sensitive Skin Symptoms as Risk Indicators for Hand Eczema 121
Pa

¨
ivikki Susitaival
Conclusions . . . . 125
References . . . . 126
11. Objectifying Primary and Acquired Sensitive Skin . . . 129
Swen Malte John
Primary and Secondary Sensitive Skin . . . . 129
Sodium Hydroxide for Skin Sensitivity Testing . . . . 130
Primary Skin Sensitivity Assessed with Sodium
Hydroxide: Swift Modified Alkali Resistance Test . . . . 131
Acquired Skin Sensitivity Assessed with Sodium Hydroxide:
Differential Irritation Test . . . . 139
Implications for Chemical Phenotyping of Sensitive Skin . . . . 141
References . . . . 145
12. Intra- and Inter-Individual Differences in Facial
Skin Biophysical Properties . . 149
F. Distante, L. Rigano, R. D’Agostino, A. Bonfigli, and
Enzo Berardesca
Introduction . . . . 149
Materials and Methods . . . . 150
Results . . . . 151
Discussion . . . . 155
References . . . . 157
Contents vii
13. Household Cleaning Products and Sensitive Skin . . 159
Ge
´
rald E. Pie
´
rard, Emmanuelle Xhauflaire-Uhoda, Carole Collard,

and Claudine Pie
´
rard-Franchimont
Introduction . . . . 159
Physiopathology of Sensory Irritation to Surfactants . . . . 160
Sensory Irritation to Household Cleaning Products . . . . 161
Experimental and Predictive Methods . . . . 162
Conclusions 165
References . . . . 165
14. Age and Gender as Influencing Factors in
Skin Sensitivity . . . . . 169
Michael K. Robinson
Introduction . . . . 169
Age and Gender Differences in Basic Skin
Biology and Physiology 171
Age and Gender Differences in Objective Skin
Irritation Responses . . . . 171
Age and Gender Differences in Objective Skin
Sensitization Responses . . . . 174
Age and Gender Differences in Sensory Irritation or
Perceptions of Skin Sensitivity . . . . 177
Summary . . . . 178
References . . . . 179
15. Sensitive Skin: Epidemiological Approach and Impact
on Quality of Life in France . . . 181
Laurent Misery, Eric Myon, Nicolas Martin,
Sylvie Consoli, The
´
re
`

se Nocera, and Charles Taieb
Background . . . . 181
Objectives . . . . 182
Methods 183
Results . . . . 184
Discussion . . . . 190
References . . . . 191
16. Fabrics and Sensitive Skin 193
Kathryn L. Hatch
Introduction . . . . 193
Fabric Feel 194
Physiological Responses . . . . 198
Skin Irritation . . . . 202
Discussion . . . . 208
References . . . . 210
viii Contents
17. Contact Urticaria Syndrome and Sensitive Skin:
Clinical Approach . . . 215
Marina Goldovsky and Howard I. Maibach
References . . . . 222
18. Contact Allergy and Sensitive Skin 225
Harald Lo
¨
ffler
Contact Allergy: The Influence of Irritation
on Type-IV Allergy . . . . 226
Contact Allergy and Unspecific Irritability . . . . 229
Contact Allergy to Type-1-Allergens and
Unspecific Irritability . . . . 230
Contact Allergy and Self-Estimated Skin Susceptibility . . . . 231

References . . . . 231
19. Photobiology and Sensitive Skin . . . 237
Giovanni Leone and Alessia Pacifico
Introduction . . . . 237
Photoirritant Contact Dermatitis . . . . 238
Tar Products . . . . 239
Furocoumarins 239
Photoallergic Contact Dermatitis . . . . 240
Sunscreens 240
Antibacterial Agents . . . . 241
Fragrances . . . . 241
Therapeutic Agents . . . . 241
Persistent Light Reaction . . . . 241
Photopatch Testing . . . . 241
References . . . . 242
20. Treatments for Sensitive Skin: An Update . . . . . . 245
Zoe Diana Draelos
Treating Visible Sensitive Skin . . . . 245
Treating Invisible Sensitive Skin . . . . 248
Algorithm for Evaluating Invisible Sensitive Skin 248
Botanical Treatment Considerations for Sensitive Skin . . . . 250
Sensitive Skin Product Guidelines . . . . 251
Summary . . . . 252
References . . . . 253
21. Tests for Sensitive Skin . . . . . . 255
Manuela Carrera and Enzo Berardesca
Introduction . . . . 255
Epidemiologic Studies 255
Contents ix
Clinical Parameters . . . . 257

Tests for Sensitive Skin . . . . 257
Quantization of Cutaneous Thermal Sensation 258
Stinging Test . . . . 259
Nicotinate Test and Erythema Following
SLS Occlusion Test . . . . 260
Evaluation of Itching Response . . . . 260
Washing and Exaggerated Immersion Tests 261
Bioengineering Tests . . . . 262
Corneosurfametry . . . . 264
Conclusions 265
References . . . . 265
22. Cosmetic Intolerance Syndrome 269
Marina Goldovsky, Patricia G. Engasser, and
Howard I. Maibach
References . . . . 273
Index . . . . 275
x Contents
Contributors
David A. Basketter Safety and Environmental Assurance Centre, Unilever
Colworth, Bedford, U.K.
Enzo Berardesca San Gallicano Dermatological Institute, Rome, Italy
A. Bonfigli Institute of Skin and Product Evaluation, Milan, Italy
Maria Breternitz Department of Dermatology and Allergology,
Friedrich-Schiller University, Jena, Germany
Manuela Carrera San Gallicano Dermatological Institute, Rome, Italy
Carole Collard Department of Dermatopathology, University Hospital Sart
Tilman, Lie
`
ge, Belgium
Sylvie Consoli Cabinet Me

´
dical, Paris, France
Karen J. Cooper Safety and Environmental Assurance Centre, Unilever
Colworth, Bedford, U.K.
R. D’Agostino Institute of Skin and Product Evaluation, Milan, Italy
F. Distante Institute of Skin and Product Evaluation, Milan, Italy
Zoe Diana Draelos Department of Dermatology, Wake Forest University
School of Medicine, Winston-Salem, North Carolina, and Dermatology
Consulting Services, High Point, North Carolina, U.S.A.
Patricia G. Engasser Department of Dermatology, University of
California, San Francisco, California, U.S.A.
Joachim W. Fluhr Department of Dermatology and Allergology,
Friedrich-Schiller University, Jena, Germany
xi
Marina Goldovsky Department of Dermatology, University of California,
San Francisco, California, U.S.A.
Kathryn L. Hatch Department of Agricultural and Biosystems
Engineering, College of Agriculture and Life Sciences, University of
Arizona, Tucson, Arizona, U.S.A.
Swen Malte John Department of Dermatology, Environmental Medicine,
Health Theory, University of Osnabrueck, Osnabrueck, Germany
Giovanni Leone Phototherapy Unit, San Gallicano Dermatologic Institute,
IRCCS, Rome, Italy
Harald Lo
¨
ffler Department of Dermatology, Philipp University of
Marburg, Marburg, Germany
Howard I. Maibach Department of Dermatology, University of California,
San Francisco, California, U.S.A.
Marie C. Marriott Safety and Environmental Assurance Centre, Unilever

Colworth, Bedford, U.K.
Nicolas Martin De
´
partement Sante
´
Publique, Laboratoires Pierre Fabre,
Boulogne, France
Francis McGlone Department of Neurological Sciences, Liverpool
University, Liverpool, U.K.
Laurent Misery CHU Morvan, Service de Dermatologie, Brest, France
Eric Myon De
´
partement Sante
´
Publique, Laboratoires Pierre Fabre, Boulogne,
France
The
´
re
`
se Nocera Laboratoires Ave
`
ne, Ave
`
ne, France
Alessia Pacifico Phototherapy Unit, San Gallicano Dermatologic Institute,
IRCCS, Rome, Italy
Manisha J. Patel Department of Dermatology, Wake Forest University
Health Sciences Center, Winston-Salem, North Carolina, U.S.A.
Marc Paye Colgate-Palmolive R&D, Milmort, Belgium

Lisa Peters Safety and Environmental Assurance Centre, Unilever Colworth,
Bedford, U.K.
Ge
´
rald E. Pie
´
rard Department of Dermatopathology, University Hospital
Sart Tilman, Lie
`
ge, Belgium
Claudine Pie
´
rard-Franchimont Department of Dermatopathology,
University Hospital Sart Tilman, Lie
`
ge, Belgium
xii Contributors
David Reilly Life Sciences Group, Unilever Research & Development,
Colworth, U.K.
L. Rigano Institute of Skin and Product Evaluation, Milan, Italy
Michael K. Robinson Procter & Gamble Company, Cincinnati,
Ohio, U.S.A.
Martin Schmelz Department of Anesthesiology and Intensive Care
Medicine, Faculty of Clinical Medicine Mannheim, University of Heidelberg,
Mannheim, Germany
Pa
¨
ivikki Susitaival Department of Dermatology, North Karelia Central
Hospital, Joensuu, Finland
Charles Taieb De

´
partement Sante
´
Publique, Laboratoires Pierre Fabre,
Boulogne, France
Emmanuelle Xhauflaire-Uhoda Department of Dermatopathology,
University Hospital Sart Tilman, Lie
`
ge, Belgium
Gil Yosipovitch Department of Dermatology, Neurobiology, and
Anatomy, Wake Forest University Health Sciences Center, Winston-Salem,
North Carolina, U.S.A.
Contributors xiii

1
What Is Sensitive Skin?
Enzo Berardesca
San Gallicano Dermatological Institute, Rome, Italy
Joachim W. Fluhr
Department of Dermatology and Allergology, Friedrich-Schiller University,
Jena, Germany
Howard I. Maibach
Department of Dermatology, University of California, San Francisco,
California, U.S.A.
Sensitive skin is a condition of subjective cutaneous hyperreactivity to environ-
mental factors. Subjects experiencing this condition report exaggerated reactions
when their skin is in contact with cosmetics, soaps, and sunscreens, and they
often report worsening after exposure to dry and cold climates.
Although no sign of irritation is commonly detected, itching, burning,
stinging, and a tight sensation are constantly present. Generally, substances that

are not commonly considered irritants are involved in this abnormal response.
They include many ingredients of cosmetics such as dimethyl sulfoxide, benzoyl
peroxide preparations, salicylic acid, propylene glycol, amyldimethylamino-
benzoic acid, and 2-ethoxyethyl methoxycinnamate (1).
Sensitive skin and subjective irritation are widespread but still far from
being completely defined and understood.
Burckhardt (2) hypothesized a correlation between sensitive skin and con-
stitutional anomalies and/or other triggering factors such as occupational skin
diseases or chronic exposure to irritants. On the other hand, Bjornberg (3) sup-
ported that no constitutional factors play a role in the pathogenesis of sensitive
1
skin, although the presence of dermatitis demonstrates a general increase in skin
reactivity to primary irritants lasting months.
Actually, sensitive skin is considered a category identified as being hyper-
sensitive to stimuli—an increased permeability of the stratum corneum and
acceleration of the nerve response in skin are considered to be involved (4).
Hyperreactors may have a thinner stratum corneum with a reduced corneocyte
area, causing higher transcutaneous penetration of water-soluble chemicals (5).
Frosch and Kligman (6), by testing different irritants, showed a 14% incidence
of sensitive skin in the normal population likely correlated to a thin permeable
stratum corneum, which makes these subjects more susceptible to chemical
irritation.
Moreover, the declined barrier function in sensitive skin has already been
reported as the result of an imbalance of intercellular lipid of stratum corneum
(7). Although impaired barrier function is easily understood as a mechanism of
sensitive skin, other factors are also possible—implications such as changes in
the nerve system and/or the structure of the epidermis. In a recent study (4),
detailed characteristics of sensitive skin have been investigated using non-
invasive methods. Sensitive skin has been classified into three different types
on the basis of their physiological parameters. Type I has been defined as the

low-barrier function group. Type II has been defined as the inflammation
group with normal barrier function and inflammatory changes. Type III has
been specified as the pseudo-healthy group in terms of normal barrier function
and no inflammatory changes. In all types, a high content of nerve growth
factor has been observed in the stratum corneum, relative to that of non-sensitive
skin. Both in Types II and III, the sensitivity to electrical stimuli was high.
As these data suggest, the hypersensitive reaction of sensitive skin is closely
related to nerve fibers innervating the epidermis.
EPIDEMIOLOGY
Many epidemiologic studies have been carried out to assess whether or not a cor-
relation with sex, age, skin type, or race could be found (8). Contradictory find-
ings have been reported. Some authors (8–10) documented a higher reactivity to
irritants mostly in females; some others noted that male subjects were direction-
ally or significantly more reactive than female (11). Other experimental studies
did not confirm this observation. Bjornberg (12), using six different irritants by
patch test application, found no sex-related differences. Moreover, Lammintausta
et al. (13), studying the response to open and patch test application of sodium
lauryl sulfate (SLS), found mild interindividual variations in transepidermal
water loss (TEWL) and dielectric water content values, but no sex-related differ-
ences in the reaction pattern.
In 1982, Frosch and Wissing (14), using dimethylsulfoxide, demonstrated a
correlation between the minimal erythema dose (MED) and the response to irri-
tants—the higher the inflammation, the lower the MED. Subsequently, a
2 Berardesca et al.
correlation between skin reactivity and skin type was reported—higher reactions
were detected in subjects with skin Type I (15). However, in a total of 110 sub-
jects covering all six skin types, the SLS dose–response generated by applying
the substance under four-hour occlusion demonstrated that there was no signifi-
cant difference between the groups. Even for Type VI skin, the dose– response
curve fell within the general pattern (16). In fact, conflicting findings have

been reported on the incidence of allergic contact dermatitis in different races
(17–20). Although there is a clinical consensus that Blacks are less reactive
and Asians are more reactive than Caucasians, the data supporting this hypothesis
rarely reach statistical significance (21). Conflicting data have also been found on
subjective (sensory) irritation. Frosch and Kligman (22) reported that most
common “stingers” were light-complexioned persons of Celtic ancestry who sun-
burned easily and tanned poorly. Grove et al. (23) found no skin type propensity
to stinging. He noted that increased stinging was related mainly to the person’s
history of sensitivity to soaps, cosmetics, and drugs. Arakami et al. (20) instead
found no significant differences after SLS testing, but significant subjective
sensory differences between Japanese and German women. So they concluded
that Japanese women may complain about stronger sensations, reflecting a differ-
ent cultural behavior rather than measurable differences in skin physiology;
however, a faster penetration of SLS in Japanese cannot be excluded.
Moreover, skin reactivity is enhanced in eczema (24). Studies performed
on animal models demonstrated that strong irritant reactions in guinea pigs sig-
nificantly reduced the threshold of skin irritation (25). In contrast, hyporeactive
states may be induced by skin treatment. Subclinical dermatitis, after repeated
cutaneous irritation by open application, may induce skin hyporeactivity (26).
This can also be one of the mechanisms of false-negative patch test.
Skin reactivity seems also to change depending on age, although contradic-
tory findings are reported in the literature. For example, Nilzen and Voss
Lagerlund (27) reported higher reactivity patch test reactions to soaps and deter-
gents in the elderly, whereas Bettley and Donoghue (28) reported a lower reac-
tivity in the same group. Coenraads et al. (29) demonstrated a higher skin
reactivity to croton oil in the older patient group, but no differences by testing
thimochinone or croton aldehyde. In 1993, Grove (30), by testing croton oil, cat-
ionic and anionic surfactants, weak acids, and solvents, reported a lower suscep-
tibility in older subjects in terms of less severe skin reactions. Recently, Robinson
(8) confirmed this lower reactivity; in fact, in his study, the oldest age cluster of

subjects (56–74 years of age) was directionally or significantly less reactive than
the younger age clusters. Moreover, Wohrl et al. (11) noted that although the rate
of positive reactions to nickel and thimerosal decreased with age, fragrance mix
and metallic mercury reactions stayed at the same level throughout all ages. The
overall sensitization rate was highest in children less than 10 years old and
decreased steadily, to be lowest among patients more than 70 years.
Patients over 70 years of age seem to have a reduced inflammatory
response either to chemical irritants or to irritation induced by ultraviolet (UV)
What Is Sensitive Skin? 3
light (31). The ultraviolet B (UVB)-induced irritation, increased in both TEWL
and DNA synthesis, was significantly diminished, with decreased epidermal
hyperplasia evident in intrinsically aged versus young mouse epidermis (32).
In contrast, following skin irritation, increased TEWL values were
recorded in the older subjects compared with the young. This finding could be
related to a deficient “early warning detection system” in the elderly. Moreover,
the skin of women in menopause becomes more sensitive to various environ-
mental threats. It has been reported that the skin gets more sensitive in women
at the beginning of menopause. This can be due to the fact that at this stage
the skin becomes thinner, with a decrease of its function as a barrier that leads
to a higher percutaneous absorption (33).
CLINICAL PARAMETERS
Sensitive skin can be defined in both subjective and objective terms. Subjective
perceptions of sensitive skin are derived from patient observations regarding
stinging, burning, pruritus, and tightness, following various environmental
stimuli. Because of the lack of clinical signs, the phenomenon of sensitive skin
is difficult to document. Attempts to identify clinical parameters in subjects
with subjective irritation indicate that these individuals tend to have a less
hydrated, less supple, more erythematous, and more teleangiectatic skin, com-
pared with the normal population. In particular, significant differences were
found for erythema and hydration/dryness (34).

CONCLUSIONS
Sensitive skin represents a widespread condition of susceptibility to exogenous
factors. To find an effective approach to improve sensitive skin, it is important
to know the detailed mechanism of sensitive skin. The reason why some subjects
react with subjective symptoms such as itching, burning, stinging, prickling, or
tingling is unclear. An increased permeability of the stratum corneum and accel-
eration of the nerve response in skin are considered to be involved (4). Approxi-
mately 40% of the population consider themselves to possess the characteristics
of sensitive skin, and 50% of these patients with sensitive skin demonstrate these
uncomfortable symptoms without accompanying visible signs of inflammation
(35). Non-invasive evaluation of sensitive skin may successfully predict individ-
ual susceptibility to cosmetic-related adverse reaction. All the efforts in this
direction appear undoubtedly important to improve tolerance to the majority of
cosmetic products. Moreover, if sensitive skin involves several different
causes, skin treatment must be selected to fit each mechanism. An appropriate
approach to improve the sensitivity of skin should be taken considering the differ-
ent mechanisms of skin sensitivity among various skin types.
4 Berardesca et al.
REFERENCES
1. Amin S, Engasser PG, Maibach HI. Side-effects and social aspects of cosmetology. In:
Baran R, Maibach HI, eds. Textbook of Cosmetic Dermatology. London: Martin
Dunitz, 1993:205.
2. Burckhardt W. Praktische und theoretische bedeutung der alkalineutralisation und
alkaliresistenzproben. Arch Klin Exp Derm 1964; 219:600.
3. Bjornberg A. Skin reactions to primary irritants in patients with hand eczema. Thesis,
Isaccsons, Goteborg, 1968.
4. Yokota T et al. Classification of sensitive skin and development of a treatment system
appropriate for each group. IFSCC Magazine 2003; 6:303.
5. Berardesca E et al. In vivo transcutaneous penetration of nicotinates and sensitive
skin. Contact Dermatitis 1991; 25:35.

6. Frosch PJ, Kligman AM. A method for appraising the stinging capacity of topically
applied substances. J Cosmet Sci 1977; 28:197.
7. Ohta M, Hikima R, Ogawa T. Physiological characteristics of sensitive skin classified
by stinging test. J Cosmet Sci Soc Jpn 2000; 23:163.
8. Robinson MK. Population differences in acute skin irritation responses. Contact
Dermatitis 2002; 46:86.
9. Agrup G. Hand eczema and other hand dermatoses in South Sweden. Academic
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