ARTICLE
Auteur(s) : Sékéné Badiaga1,2, Amélie
Menard3,4, Hervé Tissot Dupont1,5, Isabelle
Ravaux5, Didier Chouquet4, Céline
Graveriau1, Didier Raoult1, Philippe
Brouqui1,3
1Unité des rickettsies, CNRS UMR 6020, IFR 48,
Faculté de médecine, 27 bd J Moulin 13385 Marseille cedex 5
France
2Service des Urgences, CHU Nord, Marseille
3Service des maladies infectieuses et tropicales, CHU
Nord, Marseille
4Service de dermatologie, CHU Nord, Marseille
5Service des maladies infectieuses, CHU Conception,
Marseille
accepté le 20 Avril 2005
Homelessness, defined as the absence of customary and regular
access to a conventional dwelling or residence [1], is a growing
social and public health problem in wealthy western countries. The
number of homeless living in the United States, the United Kingdom
and France has been estimated at at least 500,000, 120,000, and
400,000, respectively [1-3]. Due to poor living conditions,
homeless people are affected by many infectious diseases [4]. Of
the various infections affecting homeless people, cutaneous
infections probably rank the top, presumably due to inattention to
personal hygiene and promiscuity [5-7]. However, to our knowledge,
the prevalence of skin diseases in this population has never been
investigated properly in a case-control study. This prevents us
from assessing accurately the prevalence of various infectious
diseases, including skin infections in the homeless. Such
information is necessary for planning appropriate intervention
measures for the identification, treatment and prevention of
various skin infections in homeless people. This is important,
considering the fact that the homeless have poor access to health
care systems [8]. It has been suggested that snapshot interventions
are an efficient way to manage problems of homelessness [9, 10].It
is estimated that there are about 1,500 homeless persons in
Marseilles. Of these, about 800 sleep on the streets and another
600 live in two town shelters. The remaining homeless persons sleep
in different university hospitals in and around Marseilles. Since
1993, we have been studying various aspects of louse-borne diseases
in the homeless population of Marseilles [11-13]. As part of the
study, each year we send a medical team to each of the two town
shelters designated for accommodating homeless people [10]. In 2002
and 2003, we included dermatologists in the medical team to
investigate the prevalence of various dermatological diseases in
the homeless people accommodated in those designated shelters.We
report here the prevalence of skin infections in this population as
compared to that observed in healthy control subjects resident in
Marseilles during the same period.
Patients and methods
The study protocol was reviewed and approved by the Institutional
Review Board and Ethic Committee of Marseilles (CCPPCRB99/76). As a
part of an ongoing study, a snapshot evaluation was conducted in
two shelters in Marseilles in January 2002 and 2003 [10]. Each of
the two shelters, designated herein respectively A and B, offers
300 beds. They both provide showers, clothes, food and a washing
service free of charges. A general practitioner is available two or
three times in a week to provide medical care. A registered nurse
is available daily in each shelter.
On one particular day in January, a medical team visited each of
the residential facilities referred to above. The medical team
comprised 7 nurses, 6 infectious disease residents or fellows, 4
dermatologists, and 10 other health professionals. This latter
group comprised microbiologists and infectious disease
specialists.
The residents of shelters were informed as soon as the medical
team arrived at their facility and briefed about the purposes of
the medical team’s visit. The residents were advised that a medical
team would examine them and if necessary, they would get
appropriate medical care and treatment free of charge. All cases
studied signed an informed consent form. A registered medical
practitioner interviewed and examined them and the data were
recorded on a standardized data collection sheet. Whenever
indicated, the cases were referred to a specialized center for
further evaluation and care. Scotch-tape swabs were taken when skin
lesions suggestive of scabies had been identified.
The control subjects were recruited from among individuals
seeking pre-travel advice at the clinic of Travel Medicine,
Department of Tropical and Infectious Diseases, North hospital,
University of the Mediterranean, Marseilles, France over a 4-month
period ending in September 2004. They were interviewed and examined
by the same dermatologists who later examined the cases.
Data collection and statistical analysis
Standard software was used for the storage (Entry Builder 3.0,
Microsoft® 2003, SPSS Inc. Chicago IL), retrieval and
analyses (SPSS 10.0, Microsoft®) of the data. Two tailed
tests were used for all comparisons. Differences in proportions
were tested using chi-square test or Fisher’s exact test as
appropriate. Contrasts of dimensional variables were tested using
the Student’s t test and Levene test as appropriate. Statistical
significance was defined as p < 0.05.
Results
There were 498 cases and 200 control subjects. Of the cases, a
total of 296 were recruited in 2002 and the remaining 202 cases, in
2003. Nineteen cases were recruited twice. Male cases vastly
outnumbered female cases with a male-to-female sex ratio of 14%.
Eighty-eight percent of the cases studied spoke French and a
translator helped those who could not speak French. The subjects
had been homeless less than 7 months in 45.2% of cases, from 7 to
12 months in 23.5%, from 13 to 24 months in 8.8.%, and more than 24
months in 22.9%. A majority (80%) said that they usually lived in
the same shelter where they met the medical team. Only 7.4% told
the interviewer that they slept on the streets. The rest frequented
homes of friends and relatives and cheap hotels for sleeping at
night. When asked specifically, only 7 out of 498 (1.4%) stated
that they were intravenous drug abusers. The interview was
estimated to be reliable in 47% of subjects interviewed. HIV
antibodies were found in 1 of the 498 homeless people.
The mean age (± SD) of the cases homeless was significantly
higher than that of the control subjects (41 ± 14.6 versus 35.4 ±
12.6 years; p < 0.0001. The male-to-female sex ratio was not
significantly different between controls and homeless (14.2% vs
25.6%; p = 0.33). Compared to the control subjects, a significantly
higher proportion of cases were native of north Africa (48.5% vs
4%, p < 0.001) and eastern Europe (16.2% vs 0%, p < 0.001)
while a significantly lower proportion of cases were native of
metropolitan France (28.7% vs 76.5%, p < 0.001), sub-Saharan
Africa (11.5% vs 2%, p < 0.001) and Asia (0% vs 2%, p = 0.007)
There were no statistical differences between cases and controls in
native from French overseas territories (1.8% vs 1.5%, p = 0.53),
western Europe (2.7% vs 3.5%, p = 0.73), and South America (0% vs
1%, p = 0.084).
Skin diseases (table 1)( Table 1 )
was a statistically significant occurrence (38% vs 0.5%; p <
0.0001). Compared to the control subjects, a significantly higher
proportion of cases had complaints referring to the skin (48.4% vs
2.5%; p < 0. 0001). Pediculosis (19.1% vs 0%; p < 0.0001),
scabies (3.8% vs 0%; p < 0.0001), impetigo (( figure 1 )) (2.4% vs 0% p
< 0.0001), folliculitis (4.8% vs 1.5%, p < 0.0001) and tinea
pedis (3.2% vs 0.5% ; p = 0.02%) were statistically
significant occurrences in the cases as compared the control
population. There were no statistical differences between the cases
and control subjects in terms of abscess related to intravenous
drug abuse, erysipelas (dermo-hypodermitis) and onychomycosis and
Phtirius pubis infestation. When all variables with a p value <
0.2 were included in a stepwise logistic regression model, only
pruritus, parasitism by body lice, observation of lice in clothes,
and presence of scratching lesions were independently associated
with homelessness.
Microscopic examinations of the scotch-tape swabs, taken as
above, were unrevealing in 14 cases in whom scabies was suspected.
Ten of them were treated on the spot with a single dose of
ivermectin (200 microg/kg).
Table 1 Dermatologic manifestations reported and
observed in 498 homeless compared to 200 controls
|
Variables
|
Homeless (%)
|
Control (%)
|
RR (95% CI)
|
p value*
|
|
Self-reported manifestations
|
241 (48.4)
|
5 (2.5)
|
1.72 (1.59-1.87)
|
< 0.001
|
|
Pruritus
|
181 (36.3)
|
2 (1)
|
1.61 (1.50-1.72)
|
< 0.001
|
|
Parasitism by body lice
|
80 (16.1)
|
0
|
1.48 (1.40-1.56)
|
< 0.001
|
|
Parasitism by fleas
|
36 (7.2)
|
0
|
1.43 (1.36-1.51)
|
< 0.001
|
|
Observed manifestations
|
|
|
|
|
|
Body lice (Pediculis corporis)
|
103 (20.7)
|
0
|
1.51 (1.42-1.59)
|
< 0.001
|
|
Fleas
|
2 (0.4)
|
0
|
1.40 (1.34-1.47)
|
0.369
|
|
Observed scratching lesions
|
|
|
|
|
|
of axillae
|
60 (13.5)
|
1 (0.5)
|
1.49 (1.4-1.59)
|
< 0.001
|
|
of neck
|
102 (22.8)
|
0
|
1.58 (1.48-1.68)
|
< 0.001
|
|
of thorax
|
97 (21.8
|
0
|
1.57 (1.48-1.68)
|
< 0.001
|
|
of waist
|
69 (15.8)
|
0
|
1.54 (1.45-1.64)
|
< 0.001
|
|
of socks
|
38 (8.7)
|
0
|
1.50 (1.42-1.59)
|
< 0.001
|
|
of interdigital spaces
|
15 (3.5)
|
2 (1)
|
1.30 (1.09-1.56)
|
0.093
|
|
Dermatologic diagnosis
|
190 (38)
|
11(5.5)
|
1.53 (1.41-1.65)
|
< 0.001
|
|
Pediculosis Corporis
|
95 (19.1)
|
0
|
1.50 (1.41-1.58)
|
< 0.001
|
|
Scabies
|
19 (3.8)
|
0
|
1.42 (1.35-1.49)
|
< 0.001
|
|
Impetigo
|
12 (2.4)
|
0
|
1.41 (1.35-1.49)
|
< 0.001
|
|
Folliculitis of back
|
24 (4.8)
|
3 (1.5)
|
1.26 (1.09-1.45)
|
< 0.001
|
|
Tinea pedis
|
16 (3.2)
|
1 (0.5)
|
1.33 (1.17-1.51)
|
0.023
|
|
Abscess due to IVDI
|
5 (1)
|
0
|
1.41 (1.34-1.47)
|
0.15
|
|
Dermo-hypodermitis (erysipelas)
|
7 (1.4)
|
0
|
1.41 (1.34-1.48)
|
0.119
|
|
Onychomycosis
|
26 (5.2)
|
7 (3.5)
|
1.11 (0.92-1.33)
|
0.33
|
|
Phthirus pubis
|
4 (0.8)
|
0
|
1.40 (1.34-1.47)
|
0.20
|
Discussion
The snapshot study we undertook provides us with a unique
opportunity to study the prevalence of skin diseases among homeless
persons living in the residential facilities designated for them.
Our data show a statistically significant association between
homelessness and the presence of such skin diseases as pediculosis,
scabies, tinea pedis and folliculitis. The prevalence of skin
diseases in the homeless population has been studied before [6, 14,
15]. However, these studies recruited subjects predominantly from
among homeless persons who had either been based in a hospital or
seen at a specialized dermatology outpatient facility. To the best
of our knowledge, ours is the first case-control study that
examined the prevalence of skin diseases in the homeless
population.
At the time of recruitment, 80.1% of cases included in our study
had been living in the shelters designated for homeless people and
another 7.4%, on the streets. This may not be surprising,
considering the fact that we conducted our study in January, one of
the coldest months in France. It seems more likely than unlikely
that a near-freezing temperature and an unpleasant wind in open
spaces might have discouraged many homeless people from sleeping on
the streets. Only 1% of the cases included were found to be
intravenous drug abusers. This may be attributed to the fact that
in Marseilles intravenous drug users live in the residential
facilities different from those designated for other homeless
people.
The high prevalence of pruritus and infestation by body lice, as
observed in the homeless persons studied herein is comparable to
that reported by others [11, 12]. Two cases included herein
reported previous contact with fleas, however, careful physical
examination did not detect any fleas either on their persons or in
the clothes they had been wearing. This underscores the difficulty
in detecting otherwise highly mobile ectoparasites in a state of
immobilization during the course of a single physical examination.
We were somewhat baffled by the absence of classic flea-borne
bacterial infections such as those caused by Bartonella henselae
and Rickettsia typhi and Rickettsia felis in the homeless persons
included in this study [10]. The reason for this remains unclear to
us. Pruritis and localized scratching lesions are compatible with
body-lice infection [13]. The biological plausibility of such a
notion may not be questionable, considering the fact that the body
louse injects antigens into the human hosts. These antigens provoke
allergic reactions, leading to pruritis and scratching lesions
within 3-4 weeks after they have been injected [16, 17].
Scabies was a statistically significant occurrence in cases as
compared to the control subjects. This may not be surprising, given
that homeless people often live in unhygienic conditions [5].
Furthermore, the residential facilities that accommodate them are
often overcrowded. Promiscuity is also not infrequent in the
homeless population [5].
The frequency of scabies as observed in homeless subjects herein
(3.8%) is less than that (56.5%) reported by others [14]. This
discrepancy could be explained by the fact that the study subjects
included in the reports referred to above, were recruited from
among the homeless who presented at hospitals for medical attention
[6, 14]. Furthermore, ours is part of an ongoing study that was
launched a decade ago. Understandably, the recommendations made by
the medical team during their visits to the shelters accommodating
homeless people are expected to have an impact [15] on the
prevalence of various skin diseases in the population resident at
those shelters.
In the present study, the prevalence of such superficial
bacterial skin infections as folliculitis, impetigo or ecthyma was
significantly higher in the cases as compared to controls. Our
findings were similar to those observed by others [5]. Homeless
people are at a higher risk of developing such superficial
infections, the high frequency of impetigo (ecthyma) being likely
due to skin inoculation of Streptococcus pyogenes during
scratching.
As observed in the present study, homeless people are at
increased risk of developing tinea pedis. This is mostly likely due
to poor foot hygiene, prolonged exposure to moisture, failure to
wear socks, and wearing shoes for nearly twenty-four hours [7].
Only seven of the 498 cases included in this study were
intravenous drug abusers. Due to the small number of this sample
size, it not possible to determine whether the prevalence and types
of skin infections were different in the homeless people who were
intravenous drug abusers from other homeless people studied herein.
Two studies conducted outside Marseilles did show an increase in
subcutaneous infections in homeless people who were intravenous
drug abusers [5, 6].
Unlike others [4, 5], we did not find any statistically
significant association between homelessness and such conditions as
erysipelas, onychomycosis and Phtirius pubis infestation in the
homeless population studied herein. However, caution should be
exercised in comparing the published data as various studies may
differ in term of the number of subjects evaluated, inclusion
criteria used, and regional variation in the incidence and
prevalence in various diseases.
Our study was limited by the mode of recruitment control
subjects. The control subjects were recruited from among
individuals seeking pre-travel advice, suggesting a higher
socioeconomic status of these subjects in comparison with the
general population of Marseilles. Therefore the incidence of skin
infections could be particularly low in our control population
compared to the general population of Marseilles. While the
homeless persons were enrolled in winter, the control subjects were
recruited in summer. This difference in recruitment period could
also bias the comparison of incidence of skin infections between
homeless persons and control subjects.
Despite these limitations, we submit that in Marseilles, the
prevalence of skin infections in the institutionalized homeless
population is high. These infections predominantly include
body-lice infestation, scabies, impetigo and tinea pedis.
Delousing, treatment of scabies and meticulous foot care should
reduce the burden of these skin conditions in the homeless
population.
Acknowledgements
The authors thank Dr Mohamad Khan from the University of Dhaka,
Bangladesh, for English review and suggestion.
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