Differential diagnosis of tropical skin ulcers
The woman’s family physician used the Internet to determine that the differential diagnosis of tropical skin ulcers includes localized cutaneous leishmaniasis, foreign body reaction, impetigo, pyoderma gangrenosum, bacterial or deep fungal infection, atypical mycobacterial infection, sarcoidosis, squamous and basal cell carcinoma, and superinfected insect bites. The combination of the patient’s history of potential exposure, clinical presentation, and epidemiology of leishmaniasis within the region in which she was working supports a presumptive diagnosis of localized cutaneous leishmaniasis.
Leishmaniasis
Leishmaniasis is comprised of several diverse diseases with varying degrees of severity, ranging from spontaneously healing skin ulcers to a disfiguring mucocutaneous disease, and even to fatal visceral illness. Endemic worldwide except Australia, Oceania, and Antarctica, leishmaniasis is found in the tropics and subtropics.
Approximately 2 million new cases occur each year, with markedly increasing incidence in several parts of the world resulting from international travel, immigration, military deployment, and human immunodeficiency virus coinfection.1
An estimated 10% of the world’s population is at risk for contracting leishmaniasis. Most cases reported in the US are in travelers to countries where the disease is endemic, although sporadic cases have been reported in Texas and Oklahoma.2
Characteristics
Leishmaniasis is a vector-borne disease, caused by obligate intracellular protozoa of the genus Leishmaniaand transmitted by the bite of infected female sandflies. The disease may take several forms, including cutaneous, mucocutaneous, and visceral leishmaniasis, depending on the particular Leishmaniaspecies and host response.
Localized cutaneous leishmaniasis is characterized clinically by the appearance of skin lesions at the site of the sandfly bite, which typically present as inflammatory papules before progressing to nodules and ulcers. Local lymphadenopathy may occur. Sores may be painless or painful.