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Abstract
Background/Objective: Skin lightening is a common practice in
various black communities worldwide. This affects the epidermal layer of the skin
that plays important role in innate immune function of the skin. This study
was carried out to assess immunologic skin tests and hematological indices in
the users of skin lightening creams.
Subjects and Methods: Sixty participants took part in this study.
Thirty of them were those who had used skin lightening creams for at least
two years while the remaining thirty who had never bleached served as
controls. The laboratory investigations performed included full blood count,
packed cell volume (PCV), total and differential white blood cell count),
Mantoux skin test (In vivo measurement of Type IV hypersensitivity) and skin
prick test (In vivo detection of Type 1 hypersensitivity).
Results: The mean values of PCV and neutrophils were significantly
lower while the mean value of lymphocytes was higher in the users of skin
lightening creams when compared with the controls. There was significantly
increased diameter of skin reaction to Mantoux test in the users of skin
lightening creams when compared with the controls. Skin prick test also
showed significantly increased reaction diameter with dog epithelia antigen
in the users of skin lightening creams when compared with controls.
Significantly higher proportions of the users of skin lightening creams were
positive to GS2 cockroach antigen, standardized mite antigen and mouse
epithelia antigen when compared with the controls.
Conclusion: The present study shows that skin lightening creams
cause disruption in the normal immunologic functions (Types I and IV hypersensitivity
states) of the skin and certain hematological parameters. There is need for
public awareness programs to enlighten the populace about the danger involved
in the practice of skin lightening.
Introduction
The surface of the skin is a primary site for the deposition and
introduction of microorganisms. The outermost skin layer (the epidermis)
provides the first line of defense against pathogens [1]. Therefore, the deeper layers of the skin (dermis)
remains free of infection suggesting that skin has the ability to protect
against invading microbes.
Lightening of skin is practiced by black people at all ages [2], and in both sexes with higher prevalence in young,
unmarried and educated women [3]. Skin
lightening involves the use of a wide range of products, applied to specific
or widespread area of the skin to lighten the normal black skin for fame,
cosmetic purpose and also due to misconceptions about the presumed
superiority and desirability of fair skin [4].
Most skin lightening creams contain mercury, lemon, citric
acid and even cement water. Various local skin lightening creams have no
identified active agent [9].
Studies have shown that 52.7%, 25%, 39%, and 49% of women use lightening
agents in Dakar (Senegal), Bamako (Mali), Quagadougou
and Bobo-Dioulasso (Burkina Faso) respectively [5]. A similar study also revealed an increased
in prevalence of skin lightening cream users in Lagos, Nigeria [5].
Skin lightening disrupts primary innate immune function of the epidermal
skin bleaching skin leading to susceptibility of the users to localized or
systemic infections since lightening creams used for long duration, on a
large body surface area and under hot humid conditions enhanced percutaneous
absorption [6]. In addition, higher
susceptibility to infections in these people may lead to an increased of
phagocytes in response to infections which generated free radicals, increased
utilization of antioxidants; thus lowering the antioxidant potential [7] which may lead to a state of oxidative stress
and increased in the rates of skin cancer [8].
Other side effects of skin lightening creams are damage of elastic fibers of
the skin, skin wrinkling, ochronosis, acrodynia, contact allergy, stretch
marks and ache [9]. This study is designed to
investigate the possible effects of skin lightening cream on skin immune
status by determining the skin responses to environmental antigens. Hematogical
indices of the users were also assessed.
Subjects and
Methods
A total number of sixty (60) subjects participated in this study. Thirty
(30) of them were skin bleachers who had used lightening creams for average
of 4.9 years. Another thirty (30) apparently healthy people who had never use
skin lighten creams served as controls. The subjects were recruited from
various locations within the city of Ibadan, Nigeria. All the participants
gave willing consent after the nature and objectives of the study had been
explained to them. Those with history of asthma, tuberculosis infection or
had BCG vaccine (confirmed by the mark at the upper arm) as well on
medication (e.g. immunosuppressive or antibiotic drugs) were excluded from
the study. The study had the approval of the University of Ibadan/University
College Hospital Joint Ethical Review Committee, Ibadan, Nigeria.
a. Determination of percentage PCV and counting of white blood cells:
Two (2) ml of blood specimen was collected from each participant into an
EDTA tube for full blood count. PCV was determined by standard method. Well
mixed whole blood was taken into the capillary tube through capillary
attraction. One end was sealed and the sealed capillary tube positioned
correctly in the hematocrit centrifuge. The centrifuge was switched on at
10,000 rpm for 5 minutes. The percent ratio of the packed red blood cells to
the whole blood is the PCV read on the hematocrit reader.
White blood cells were counted as described in standard texts. Diluting
fluid (0.38ml) was dispensed into a tube and 20µl of blood sample was added.
Improved Neubauer ruled counting chamber (hemocytometer) was filled by
holding capillary tube, containing the blood sample, at an angle 450 and
slightly touched the tip against the edge of the coverglass. The chamber was
left undisturbed for 2 minutes after which it was placed on microscope stage
and the white blood cells were counted in a specified area using 10 x
objective.
b. Skin Prick Test:
The test was performed on the forearm. The forearm was sterilized with
methylated spirit, and a drop of commercially - produced allergenic extracts
(Standardized cat hair, Dog epithelia mixed breeds, GS9 Southern grass mix,
GS2 Cockroach mix, Mango blossom Magnifera indica, Mixture of standardized mite,
Mouse epithelia and GS mold #3 (GREER brand, USA) were placed onto marked
areas of the skin using a dropper. Histamine was used as a positive control
and saline solution as the negative control. With a sterile special lancet, a
small prick through the drops was made. This was to allow a small amount of
allergens to enter the skin. The diameter of induration was measured after 20
minutes of skin prick using ruler. The diameter of induration greater than
3mm is regarded as positive.
c. Mantoux test:
The test involved the injection 0.1ml of 5IU of purified protein
derivative (PPD) into the skin intradermally using insulin syringe after been
sterilized with alcohol. The subjects were instructed not to scratch the site
of injection and the area was examined at 48-72 hours after the injection.
The wheal and flare reaction was measured by measuring the diameter of
induration with meter ruler.
Results
Sixty participants took part in this study. Thirty of these were those
using skin lightening creams while the remaining thirty that were not using
skin lightening cream served as controls. All participants in this study were
females. The age mean of subjects was 26.9±2.7 years while that of controls
was 25.9±3.8years. There was no statistically significant difference between
the ages of the test and control subjects.
In Table 1, the results of full blood count comprising packed cell volume
(PCV), total and differential while blood cells count were presented. The
mean percentage value of PCV in test subjects was 36 ±3 % while it was 38± 2%
in controls. There was statistically significant decrease in the mean level
of test subjects when compared with controls. The mean value of total white
blood cells count in test subjects was 5,200±1100/mm3 while it was
5,400±900/mm3 in controls. There was no statistically significant
difference in the mean value of test subjects compared with controls. The
mean value of neutrophils in test subjects was 2,900±69/mm3 while
it was 3,200±43/mm3 in controls. There was statistically significant
decrease in the mean value of test subjects when compared with controls. The
mean value of lymphocytes in test subjects was 2,200±64/mm3 while
it was 2,000±46/mm3 in controls. There was statistically
significant increase in the mean value of subjects when compared with
controls. The mean values of monocytes,
eosinophils, basophils in the test subjects were 125±11/mm3,
42±9/mm3, and 4±3/mm3 while corresponding values in the
controls were 119±7/mm3, 34±5/mm3, and 4±2/mm3.
There were no statistically significant differences.
Table 2 presents comparison (Mean ± S.D) of diameter of skin reaction
during Mantoux and skin prick test. The mean diameter of Mantoux test in skin
lightening cream users was 4.2±2.8mm while it was 1.4±2.3mm in controls.
There was statistically significant difference in the mean value of bleachers
when compared with controls. The mean diameter of skin prick test using
allergic extracts of standardized cat hair, dog epithelia mixed breeds, GS9
southern grass mix, GS2 cockroach mix, mango blossom Magnifera indica,
mixture of standardized mite, mouse epithelia and GS mold mix #3 were
2.8±0.9mm, 3.3±0.5mm, 3.0±0.9mm, 3.3±0.7mm, 2.6±0.8mm, 2.9±9mm, 3.0±0.9mm,
2.1±0.3mm respectively while the corresponding values in controls were
2.0±0.6mm 2.6±0.5mm, 3.3±0.5mm, 3.0±0.8mm, 2.5±0.8mm, 2.3±.0.5mm,
2.3mm±0.2mm. There was statistically significant increase in skin prick
diameter in test subjects using dog epithelia mixed breeds antigen when
compared with controls while other allergic extracts showed no statistically
significant differences in test subjects compared with controls.
Table 3 presents the comparison (Chi-square) prevalence of positive skin
prick reactions in subjects and controls. The prevalence of positive skin
prick reactions in the subjects using allergic extracts of standardized cat
hair, dog epithelia mixed breeds, GS9 southern grass mix, GS2 cockroach mix,
mango blossom Magnifera indica, mixture of standardized mite, mouse epithelia
and GS Mold mix #3 were 6.7%, 20%, 16.7%, 56.7%, 13.3%, 26.7%, 23.3%, 3.3%
respectively while the corresponding prevalence in controls were 0%, 16.7%,
13.3% 23.3% 10.0%, 6.7% 3.3%, 0%. There were significant higher prevalence of
positive skin reactions to GS2 cockroach mix and mixture of standardized mite
in the subjects when compared with controls.
|
Parameters
|
Tests (n=30)
|
Controls (n=30)
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t-
|
p
|
|
PCV (%)
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36±3
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38±2
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2.732
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0.008*
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WBC (/mm3)
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5,200±1,100
|
5,400±900
|
0.916
|
0.346
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Neut. (/mm3)
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2,900±69
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3,200±43
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3.27
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0.002*
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Lymph (/mm3)
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2,200±64
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2,000±46
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3.388
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0.001*
|
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Mono. (/mm3)
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125±11
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119±7
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0.727
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0.47
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Eosin. (/mm3)
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42±9
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34±5
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0.901
|
0.371
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Baso. (/mm3)
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4±3
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4±2
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1.439
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0.155
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*=significantly different from the controls.
Table1. Mean and standard deviation of Full Blood Count in test
subjects compared with controls.
|
Parameters
(mm)
|
Test (n=30)
|
Controls (n=30)
|
t-
|
p
|
|
Mantoux
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4.2±2.8
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1.4±2.3
|
4.266
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0.000*
|
|
Standardized
cat hair
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2.8±0.9
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2.0±0.6
|
0.701
|
0.534
|
|
Dog
epithelia mixed breeds
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3.3±0.5
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2.6±0.5
|
2.53
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0.026*
|
|
GS9
Southern grass mix
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3.0±0.9
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2.6±0.5
|
1.075
|
0.302
|
|
GS2
Cockroach mix
|
3.3±0.7
|
3.3± 0.5
|
0.167
|
0.869
|
|
Mango
blossom-Magnifera indica
|
2.6± 0.8
|
3.0±0.8
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0.808
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0.435
|
|
Mixture
of standardized mite
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2.9±0.9
|
2.5±0.8
|
0.854
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0.404
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|
Mouse
epithelia
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3.0±0.9
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2.3±0.5
|
1.566
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0.141
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|
GS
mold mix #3
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2.1±0.3
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2.3±0.2
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0.289
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0.779
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*=significantly different from the controls.
Table 2: The diameter (Mean ± S.D) of skin reaction to various
antigens in test subjects and controls.
|
Parameters
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Positive
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Negative
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Chi-square
|
P
|
|
Standardized cat hair:
|
|
|
|
|
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Test subjects
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2
|
28
|
|
|
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Controls
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0
|
30
|
2.069
|
0.15
|
|
Dog epithelia:
|
|
|
|
|
|
Test subjects
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6
|
24
|
|
|
|
Controls
|
5
|
25
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0.111
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0.739
|
|
GS9 Southern
Grass:
|
|
|
|
|
|
Test subjects
|
5
|
25
|
|
|
|
Controls
|
4
|
26
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0.131
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0.718
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|
GS2 Cockroach Mix:
|
|
|
|
|
|
Test subjects
|
17
|
13
|
|
|
|
Controls
|
7
|
23
|
6.944
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0.008*
|
|
Mango blossom:
|
|
|
|
|
|
Test subjects
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4
|
26
|
|
|
|
Controls
|
3
|
27
|
0.162
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0.688
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|
Mixture of
mites:
|
|
|
|
|
|
Subjects
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8
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22
|
|
|
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Control
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2
|
28
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4.32
|
0.038*
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|
Mouse
Epithelia:
|
|
|
|
|
|
Test subjects
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7
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23
|
|
|
|
Controls
|
1
|
29
|
5.192
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0.023*
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|
GS mold Mix
#3:
|
|
|
|
|
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Test subjects
|
1
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29
|
|
|
|
Controls
|
0
|
30
|
1.017
|
0.313
|
*=significantly different from the controls.
Table 3: The comparison of prevalence of positive skin prick
reaction in test subjects and controls.
Discussion
The epidermis layer of the skin plays important role in the body
immunological defense against pathogens. To knowledge of the investigator of
the present study, no report has related the act of skin lightening with
disruption of innate immune function of the skin.
Whenever the skin immune defense mechanism is impaired, the skin is
expected to become prone to various infections. The presence of infectious
agents will mobilize the polymorphonuclear cells (PMN) to the site of
infection, thereby causing reduced circulating neutrophils. In this study,
the mean level of circulating neutrophils was found to be significantly lower
while the mean level of circulating lymphocytes was found to be significantly
higher in test subjects compared with the controls. Thus, suggesting
possibility of localized infection of the skin. It was previously reported
that in a localized bacterial infection, there is mobilization of the blood
neutrophils to the sites of the infection causing reduced level of
circulating in the system circulating [11].
Moreover, users of skin lightening creams have been reported to be prone to
various skin infections of bacterial or fungi origins [10]. There was no such report or finding in the users of
lightening creams in this environment.
The mean level of packed cell volume in test subjects was significantly
lower in the test when compared with the controls. This might be due to RBC
destruction by skin lightening creams that entered blood circulation through
permeabilised skin. According to Halder and Nootheti [12], free
radicals are generated by components of skin lightening creams which causes
red blood cell membrane damage through lipid peroxidation or direct RBC
attack.
Positive Mantoux skin test reaction suggests the presence of activated
phagocytes due to infection by Mycobacterium tuberculosis or
environmental Mycobacteria. The diameter of Mantoux skin reaction to purified
protein antigen was significantly higher in test subjects compared with
controls. The Mantoux skin reaction diameter of 10mm and above is accepted as
exposure to M. tuberculosis, therefore part of diagnosis of pulmonary
tuberculosis. The result of larger diameter of Mantoux test in subjects using
skin lightening creams could not be readily explained but it may be
hypothesized that may be cross-reaction antigens in the skin of lightening
cream users that mimicked Mycobacterium tuberculosis.
The skin prick test is a diagnostic tool in the assessment of immediate
hypersensitivity. The results from skin prick tests can be used to guide in
the management of patient with asthma and hay fever, e.g. desensitization to
a certain allergen, removal of a family pet, and avoidance of certain foods.
The mechanism of reaction involves preferential production of IgE which has
very high affinity for its receptor on mast cells and basophils. These mast
cells may also be triggered by chemicals but such reaction mediated by
chemical agents without IgE-allergen interactions are not classical Type 1
hypersensitive reactions. In the present study, the users of skin lightening
creams were found to positively react to dog epithelia mixed breeds, GS2
Cockroach mix, and mixture of standardized mite and mouse epithelia when
compared with controls. This suggested possible sensitization of immune cells
in those using skin bleaching creams probably due to chemical assault on the
skin. The results of skin prick test might also be due to the fact that
certain components of skin lightening cream mimicked immune responses to dog
epithelia, cockroach, mite and mouse epithelia
allergens. Biebl and Warshaw
[13] previously reported the occurrence of
contact dermatitis cosmetic users.
In conclusion, the skin lightening creams disrupts the normal immunologic
functions of the skin. Thus, the use of Mantoux skin test to screen for
tuberculosis infection or Type IV hypersensitivity state and the use of skin
prick test to screen for Type 1 allergic reaction to environmental allergen
may not be useful to the users of skin lightening creams.
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