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Skin Infections in Travelers
By Lin H. Chen, MD
Dr. Chen is Assistant Clinical Professor, Harvard Medical School, Director, Travel Medicine Center, Mt. Auburn Hospital, Cambridge, MA.
Dr. Chen reports no financial relationships relevant to this field of study.
Synopsis: Skin and soft-tissue infections are significant travel-related dermatologic conditions and commonly are associated with insect bites. These findings underscore the importance of bite prevention.
Source: Hochedez P, Canestri A, Lecso M, et al. Skin and soft tissue infections in returning travelers. Am J Trop Med Hyg 2009;80(3):431-4.
The authors from Paris, France, described 60 adult travelers diagnosed with skin and soft-tissue infections (SSTI) seen between January 1, 2006, and August 30, 2007. Males comprised 63%, the mean age was 42 years, and the median duration of stay abroad was 15 days. The majority of cases developed lesions abroad (73%), whereas the remaining cases developed lesions after a median of 3 days after return. The majority of patients had traveled to Africa (57%), followed by Asia (10%), South America (8%), Indian Ocean (8%), Pacific (8%), Caribbean (7%), and North America (2%). Tourism was the most common reason for travel (68%), followed by business (18%), visiting friends or relatives (10%), expatriates (3%).
The most common clinical presentations were impetigo (35%) and cutaneous abscesses (23%), followed by ecthyma (18%), cellulitis (18%), and furuncles and folliculitis (5%). The predominant affected area was a lower limb (75%). Overall, 57% of patients had a history of insect bites in the same area of SSTI, including mosquitoes, spiders, fleas, and horseflies. Among those with bacterial isolates, 43% had Staphylococcus aureus, 34% had group A β-hemolytic Streptococcus infections, and 23% were infected with both organisms. Panton-Valentine leukocidin was present in 4 patients with severe infection. No methicillin-resistant S. aureus (MRSA) was identified. Infection required hospitalization in 2 patients with cellulitis and surgery in 5 patients for abscesses.
Skin and soft-tissue infections are common health problems associated with travel. A recent analysis of international travelers presenting to travel clinics in the GeoSentinel Surveillance Network found that among 4,594 diagnoses reported after travel, 18% were dermatologic; 6.8% of the dermatologic diagnoses were superinfected insect bites, and 12.8% were attributed to pyodermas (cellulitis, skin abscess, erysipelas).1 A study from the same French unit covering November 2002 to May 2003 reported 35 cases of SSTI (21 infectious cellulitis and 14 pyoderma) among 165 travelers who returned from the tropics.2 The Hochedez study focuses on SSTI and presents informative results regarding adult travelers. The study excluded travelers younger than 15 years of age and patients who had impetiginized scabies and marine envenomation. Therefore, we cannot draw conclusions regarding SSTI in pediatric travelers or in travelers with marine exposures.
The high proportion of patients with SSTI who reported a history of insect bites highlights the need for bite prevention. The predominance of S. aureus and group A β-hemolytic Streptococcus, the most common pathogens in ordinary skin infections, speaks to the importance of intact skin in the prevention of SSTIs. The study reassures that to date, MRSA is not a common pathogen associated with SSTI in such travelers. However, the increasing incidence of community-acquired MRSA globally portends an emerging infection with travel association.
Panton-Valentine leukocidin (PVL) is a cytotoxin produced by S. aureus and causes severe necrosis, leads to high rates of transmission, and has been reported in travel-associated SSTI.3 The presence of this gene in S. aureus indicates increased virulence, resembling methicillin-resistant S. aureus.4 Hochedez, et al. reported that 27% PVL-positivity in their isolates of S. aureus, including an isolate from a woman who returned from Ivory Coast with recurrent infections and later led to infection in a male companion.
The key messages of the report by Hochedez et al are: bacterial infections of skin and soft-tissue contribute significant morbidity; insect bites predispose travelers to these problems; bite prevention and self-treatment of bacterial superinfection should be discussed; and consider checking for the presence of PVL in S. aureus isolates associated with virulent or recurrent infections. Prevention of the leading causes of dermatologic problems in travelers should include insect bite avoidance. Although clinicians evaluating returned travelers should consider the exotic diagnoses such as cutaneous larva migrans, leishmaniasis, and African tick bite fever, they must also suspect common, ubiquitous bacterial pathogens.