Description
Next to fever and diarrheal illness, skin problems are the third most frequent medical problem in returned travelers reported to travel and tropical medicine clinics (1). Insect bites, not infrequently associated with secondary infection, are by far the most common dermatologic problem (2). Occasionally, a hypersensitivity reaction to bites may occur, leading to persistent or waxing and waning signs and symptoms or pruritic papular lesions lasting many months. Topical steroids and antihistamines may be helpful. Scabies must always be a consideration in the case of a generalized pruritic, papular rash.
NODULAR LESIONS
Recurrent pyoderma, in the form of furunculosis, may occur independently of bites as a result of colonization of the skin and nasal mucosa with Staphylococcus aureus. An intranasal anti-staphylococcal antibiotic (e.g., mupirocin)—alone or in combination with rifampin and an additional anti-staphloccocal agent—may be recommended to attempt eradication of colonization. Another painful boil-like lesion, often acquired in Africa and Latin America, is caused by an infection with the larval stage of the Tumbu (Cordylobia anthropophaga) or bot fly (Dermatobium hominis), respectively. The presence of a small, central punctum that allows the maggot to breath differentiates this condition (myiasis) from a boil. The stoma may be occluded with petrolatum jelly for one or more hours until the larva can be pulled or squeezed out (3). Another ectoparasite that produces a nodular, subcutaneous lesion on the foot is the sand flea (Tunga penetrans). Tungiasis is characterized by a painful, nodular lesion (with a central dark spot), which is actually the enlarged and egg-filled female sand flea uterus. Extracting the flea surgically is the treatment of choice.
LINEAR LESIONS
Of the linear lesions, cutaneous larva migrans, an infection with a dog or cat hookworm, is the most frequent. Infection is characterized by a very pruritic, serpiginous, linear lesion that migrates within the skin at the rate of 2-4 cm per day, most frequently on the feet. Occasionally, bullous formation, as a result of a severe inflammatory reaction, may lead to painful lesions. Treatment is with albendazole or ivermectin (4). When lime juice or another plant-derived psoralen comes in contact with the skin, an exaggerated sunburn may occur (phytophotodermatitis), giving rise to a linear, almost straight, asymptomatic lesions followed by hyperpigmentation. The pigment colour may take many weeks to resolve (5).
SKIN ULCERS
In patients who present with persistent cutaneous ulcers, the diagnosis of leishmaniasis (see the Leishmaniasis section of this chapter) must be considered. This chronic, often painful ulcer with heaped-up margins is acquired by the bite of a sand fly, most often in Latin America. It must be distinguished from pyodermas, mycobacterial, and subcutaneous fungal infections. Diagnosis is made by culture of a scraping of the base of the lesion, biopsy, and serology. The use of local or systemic therapy will be determined by knowing the likely species of the parasite and the cosmetic effect of the lesion (6).
FEVER AND RASH
Fever and rash in returned travelers is most often due to a viral infection, with dengue being the most frequent ‘exotic’ infection. Enteroviruses, such as Echovirus and cocksackie virus, hepatitis B, measles, Epstein-Barr virus, typhus, leptospirosis, HIV, and chikungunya fever are but a few of the systemic infections that must be considered. Rickettsial infections as well often present with fever and diffuse rash, or an eschar, in the case of some of the tick-borne diseases. Hemmorhagic fevers are of particular concern because of the need for rapid treatment, as in the case of meningococcal meningitis, and the public health risks associated with Lassa fever, Marburg, and Ebola viruses (7, 8).
