Dermatologic Complications From Sojourns Abroad

Global travel has become ubiquitous for recreational, occupational, educational, humanitarian, and other purposes. For this reason, those who travel may encounter and acquire diseases from countries outside their normal habitat. A recent fascinating session from the Summer American Academy of Dermatology Meeting, “Infectious Disease and Infestations in Returned Travelers: The Americas,” highlighted current trends relating to this phenomenon.

Dr. Natasha Mesinkovska noted that Americans are most likely to travel within the Americas, particularly to Mexico, Canada, and the Dominican Republic, but also to England and France. Conversely, approximately 66 million visitors from other regions visit the United States annually. GeoSentinel surveillance clinics suggest that diarrhea and febrile illness, such as malaria, are the most common concerns reported among returning travelers who are ill. Dermatologic concerns account for approximately 18% of all problems (Int J Infect Dis. 2008;12:593-602), and many of these are either cosmopolitan infections (eg, scabies, herpes, staphylococcal) or specific tropical infections (eg, cutaneous larva migrans, tungiasis, leishmaniasis, myiasis). Because many tropical infections are associated with insect vectors, particularly mosquitoes, the prophylactic use of repellant products such as 30% to 35% DEET is advisable. Also, travelers should avoid contact with sand, soil, stagnant water, and farm animals; drink only pasteurized liquids; close hotel windows; and sleep under mosquito netting, where appropriate.

Dr. Ron (Ronald) Rapini reviewed the various diagnostic procedures that may be used for unusual infections associated with the Americas. Diagnostic techniques include potassium hydroxide preparation, routine biopsy, biopsy with special stains, culture, and serologic testing. For example, South American blastomycosis is associated with 90% sensitive and 80% specific serologic test, and Gomori methenamine-silver or Periodic acid–Schiff stains may reveal the characteristic mariner’s wheel organisms in tissue.

Dr. Dirk Elston reviewed the nuances of dealing with worms and insects. Ivermectin may be given to kill the maggots that cause myiasis; the dead maggots can then be easily removed about a week later, as spines that lodge them into the tissue have retracted. A snake venom extractor may be utilized to suck these maggots out of infested tissue. Recurring scabies may lead to chronic impetigo and thence to glomerulonephritis and renal failure. Use of the dermatoscope may aid in the diagnosis of scabies. Many cases of so-called prurigo nodularis may actually be due to repeated bed bug bites. Both reduviid bugs and wild and domestic mammals have been found to harbor the etiologic trypanosomes of Chagas disease within the continental United States (Clin Microbiol Rev. 2011;24:655-681). Cyclic fevers should at least suggest the diagnosis of the tick-borne illness babesiosis.

Dr. Jose Dario Martinez reviewed the problem of “rash and fever.” Among the common culprits associated with such a presentation are dengue and chikungunya. Both are mosquito borne and both have now been seen in the United States, most commonly in returning travelers but also rarely as autochthonous infection. “Islands of normal in a sea of red”–appearing skin associated with fever, headache, retro-orbital pain, any sign of bleeding diathesis, and thrombocytopenia suggests dengue hemorrhagic fever. IgM serologic tests may be positive approximately 5 days into the infection, but polymerase chain reaction tests may be even more rapid. Promising work on a 3-dose quadrivalent dengue vaccine recently has been published (Lancet. July 10, 2014. doi:10.1016/S0140-6736(14)61142-9). Chikungunya, once previously limited to parts of Asia and Africa, is now present in the Americas. As of August 2014, local transmission had been identified in 31 countries or territories in the Caribbean, Central America, South America, or North America including the United States. Clinically, this disorder resembles dengue with less bleeding diathesis and more severe polyarthralgia. Reverse transcription–polymerase chain reaction testing can confirm the diagnosis in less than a week after infection. Treatment is supportive only, and a vaccine is under testing.

I discussed the ever-expanding worldwide epidemic of bed bug infestation, as verified by reports on a global bed bug registry Web site. Although bed bugs have not yet been reported to transmit disease to humans, the bite is pruritic and may be associated with severe emotional ramifications (Psychosomatics. 2012;53:85-91). Bed bugs can be detected by visual inspection of typical hiding places within 3 feet of the bed; expensive but very sensitive lures and bed bug–detecting canines also can be used to verify an infestation. Clearing bed bug infestations may require a complex multipronged approach, including thorough vacuuming and steaming, placing traps and desiccants, spreading insecticides, and thermal remediation. To avoid bringing bed bugs into the home following a trip, travelers are advised to check for bed bug infestation of hotel rooms, keep luggage off the floor and hang clothing up high, and launder clothes immediately upon returning home.