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Dermoscopy of Tungiasis

Dermoscopy of Tungiasis Tungiasis is an endemic parasitic disease in South and Central America, Africa, Asia, and the Caribbean,1 and it is a major public health problem among the very poor.2 Increasing travel has resulted in spread of the disease to countries like the United States, Australia, and Central Europe,3 where tungiasis is little known. Usually tungiasis is acquired by walking barefoot in humid sand contaminated by feces from pigs and cows, which are the preferred hosts of the sand flea Tunga penetrans. The fertilized female parasite penetrates the epidermis and nourishes on blood in the superficial dermis. Covered by reactive epidermal hyperplasia, the flea develops to a final size of about 6 mm. Early diagnosis and therapy of tungiasis is crucial to avoid frequent complications caused by bacterial infections with a wide spectrum of pathogens.1 Report of a Case. A 51-year-old man developed multiple light-brown itching papules on both feet after vacationing in northwest Brazil. Prior to his hospital admission, the papules were thought to be multiple abscesses, and 1 of them was incised, which resulted in severe local inflammation. At the Department of Dermatology, the patient presented with 10 light-brown papules distributed on his soles and toes and subungually (Figure 1A). The papules had a diameter of 4 to 5 mm and a small central dark spot. Using a handheld dermoscope, we identified the dark spots as pigmented rings with central pores (Figure 1 B). The diagnosis of tungiasis was made, and all parasites were excised using a 6-mm punch. Diagnosis was confirmed by histopathologic analysis (Figure 2). Oral floxacillin was administered to treat Staphylococcus aureus infection. The patient had received a recent immunization against tetanus toxoid. Figure 1. View LargeDownload A, Subungual tungiasis. B, Dermoscopy image of the same lesion showing the posterior abdomen of Tunga penetrans (arrowheads) with a central pigmented ring (arrow) that corresponds to the pigmented chitin surrounding the posterior opening of the exoskeleton (original magnification ×20). Figure 2. View LargeDownload Histopathologic image of Tunga penetrans showing the partially brown pigmented chitin of the exoskeleton (arrowheads), which corresponds to the pigmented ring seen under dermoscopy (hematoxylin-eosin, original magnification ×100). Comment. Outside of endemic areas, tungiasis is frequently misdiagnosed as plantar or subungual warts, subungual exostosis, myiasis, ecthyma, bulla repens, or abscesses. Diagnostic incision and manipulations frequently result in secondary cellulitis, erysipelas, tetanus, or septicemia. This can be avoided by early diagnosis and surgical excision.1 Simple incision does not allow expulsion of the parasite because spicules of the chitin exoskeleton are interlocked with the surrounding reactive hyperkeratosis. Dermoscopy is well established for use in diagnostic classification of melanocytic and nonmelanocytic skin tumors and especially in the diagnosis of early melanoma.4 Moreover, dermoscopy is valuable in detecting scabies mites. As shown in the present study, dermoscopy also allows rapid diagnosis of tungiasis. The central brown spot seen with the naked eye (Figure 1 A) can be identified at 20-fold magnification as a typical brown-pigmented ring with a central pore (Figure 1 B) that corresponds to the pigmented chitin surrounding the posterior opening of the flea exoskeleton. Histopathologic analysis shows that the brown ring is a less eosinophilic pale to slightly brown part of the exoskeleton (Figure 2).5 In conclusion, tungiasis is a frequent problem in the tropics, and tourists are increasingly affected. The awareness of the clinical presentation is mandatory in nonendemic countries, and dermoscopy can help to rapidly confirm the diagnosis and initiate appropriate therapy. The authors have no relevant financial interest in this article. References 1. Feldmeier HHeukelbach JEisele MSousa AQBarbosa LMCarvalho CB Bacterial superinfection in human tungiasis Trop Med Int Health. 2002;7559- 564PubMedGoogle ScholarCrossref 2. Heukelbach Jde Oliveira FAHesse GFeldmeier H Tungiasis: a neglected health problem of poor communities Trop Med Int Health. 2001;6267- 272PubMedGoogle ScholarCrossref 3. Caumes ECarriere JGuermonprez GBricaire FDanis MGentilini M Dermatoses associated with travel to tropical countries: a prospective study of the diagnosis and management of 269 patients presenting to a tropical disease unit Clin Infect Dis. 1995;20542- 548PubMedGoogle ScholarCrossref 4. Mayer J Systematic review of the diagnostic accuracy of dermatoscopy in detecting malignant melanoma Med J Aust. 1997;167206- 210PubMedGoogle Scholar 5. Smith MDProcop GW Typical histologic features of Tunga penetrans in skin biopsies Arch Pathol Lab Med. 2002;126714- 716PubMedGoogle Scholar http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Archives of Dermatology American Medical Association

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Publisher
American Medical Association
Copyright
Copyright © 2004 American Medical Association. All Rights Reserved.
ISSN
0003-987X
eISSN
1538-3652
DOI
10.1001/archderm.140.6.761
Publisher site
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Abstract

Tungiasis is an endemic parasitic disease in South and Central America, Africa, Asia, and the Caribbean,1 and it is a major public health problem among the very poor.2 Increasing travel has resulted in spread of the disease to countries like the United States, Australia, and Central Europe,3 where tungiasis is little known. Usually tungiasis is acquired by walking barefoot in humid sand contaminated by feces from pigs and cows, which are the preferred hosts of the sand flea Tunga penetrans. The fertilized female parasite penetrates the epidermis and nourishes on blood in the superficial dermis. Covered by reactive epidermal hyperplasia, the flea develops to a final size of about 6 mm. Early diagnosis and therapy of tungiasis is crucial to avoid frequent complications caused by bacterial infections with a wide spectrum of pathogens.1 Report of a Case. A 51-year-old man developed multiple light-brown itching papules on both feet after vacationing in northwest Brazil. Prior to his hospital admission, the papules were thought to be multiple abscesses, and 1 of them was incised, which resulted in severe local inflammation. At the Department of Dermatology, the patient presented with 10 light-brown papules distributed on his soles and toes and subungually (Figure 1A). The papules had a diameter of 4 to 5 mm and a small central dark spot. Using a handheld dermoscope, we identified the dark spots as pigmented rings with central pores (Figure 1 B). The diagnosis of tungiasis was made, and all parasites were excised using a 6-mm punch. Diagnosis was confirmed by histopathologic analysis (Figure 2). Oral floxacillin was administered to treat Staphylococcus aureus infection. The patient had received a recent immunization against tetanus toxoid. Figure 1. View LargeDownload A, Subungual tungiasis. B, Dermoscopy image of the same lesion showing the posterior abdomen of Tunga penetrans (arrowheads) with a central pigmented ring (arrow) that corresponds to the pigmented chitin surrounding the posterior opening of the exoskeleton (original magnification ×20). Figure 2. View LargeDownload Histopathologic image of Tunga penetrans showing the partially brown pigmented chitin of the exoskeleton (arrowheads), which corresponds to the pigmented ring seen under dermoscopy (hematoxylin-eosin, original magnification ×100). Comment. Outside of endemic areas, tungiasis is frequently misdiagnosed as plantar or subungual warts, subungual exostosis, myiasis, ecthyma, bulla repens, or abscesses. Diagnostic incision and manipulations frequently result in secondary cellulitis, erysipelas, tetanus, or septicemia. This can be avoided by early diagnosis and surgical excision.1 Simple incision does not allow expulsion of the parasite because spicules of the chitin exoskeleton are interlocked with the surrounding reactive hyperkeratosis. Dermoscopy is well established for use in diagnostic classification of melanocytic and nonmelanocytic skin tumors and especially in the diagnosis of early melanoma.4 Moreover, dermoscopy is valuable in detecting scabies mites. As shown in the present study, dermoscopy also allows rapid diagnosis of tungiasis. The central brown spot seen with the naked eye (Figure 1 A) can be identified at 20-fold magnification as a typical brown-pigmented ring with a central pore (Figure 1 B) that corresponds to the pigmented chitin surrounding the posterior opening of the flea exoskeleton. Histopathologic analysis shows that the brown ring is a less eosinophilic pale to slightly brown part of the exoskeleton (Figure 2).5 In conclusion, tungiasis is a frequent problem in the tropics, and tourists are increasingly affected. The awareness of the clinical presentation is mandatory in nonendemic countries, and dermoscopy can help to rapidly confirm the diagnosis and initiate appropriate therapy. The authors have no relevant financial interest in this article. References 1. Feldmeier HHeukelbach JEisele MSousa AQBarbosa LMCarvalho CB Bacterial superinfection in human tungiasis Trop Med Int Health. 2002;7559- 564PubMedGoogle ScholarCrossref 2. Heukelbach Jde Oliveira FAHesse GFeldmeier H Tungiasis: a neglected health problem of poor communities Trop Med Int Health. 2001;6267- 272PubMedGoogle ScholarCrossref 3. Caumes ECarriere JGuermonprez GBricaire FDanis MGentilini M Dermatoses associated with travel to tropical countries: a prospective study of the diagnosis and management of 269 patients presenting to a tropical disease unit Clin Infect Dis. 1995;20542- 548PubMedGoogle ScholarCrossref 4. Mayer J Systematic review of the diagnostic accuracy of dermatoscopy in detecting malignant melanoma Med J Aust. 1997;167206- 210PubMedGoogle Scholar 5. Smith MDProcop GW Typical histologic features of Tunga penetrans in skin biopsies Arch Pathol Lab Med. 2002;126714- 716PubMedGoogle Scholar

Journal

Archives of DermatologyAmerican Medical Association

Published: Jun 1, 2004

Keywords: tunga penetrans infestation,dermoscopy

References