Article
Furuncular Myiasis in 2 American Travelers Returning From Senegal
Furuncular myiasis caused by Cordylobia anthropophaga larvae is commonly seen in Africa but rarely is diagnosed in travelers returning from the...
Leishmaniasis describes any disease caused by protozoan parasites of the genus Leishmania1 and can manifest in 3 different forms: cutaneous (the most common); mucosal, a destructive metastatic sequela of the cutaneous form; and visceral, which is potentially fatal.2 According to the World Health Organization, the leishmaniases are endemic in 88 countries.3 It is estimated that 95% of cutaneous cases occur in the Americas (most notably Central and South America), the Mediterranean basin, the Middle East, and Central Asia.2 Most cutaneous cases diagnosed among nonmilitary personnel in the United States are acquired in Mexico and Central America.4 In Central and South America, the causative human pathogens include species of the Leishmania (Viannia) complex (eg, Leishmania panamensis, Leishmania braziliensis, Leishmania guyanensis, Leishmania peruviana) and the Leishmania mexicana complex (eg, Leishmania mexicana, Leishmania amazonensis, Leishmania venezuelensis). All of these species can cause localized cutaneous lesions, but only L panamensis, L braziliensis, and L guyanensis are associated with metastatic mucosal lesions. In Central and South Americas, only Leishmaniasis chagasi (also known as Leishmaniasis infantum) is known to cause visceral leishmaniasis.5
Case Report
A 26-year-old man was referred to the dermatology clinic by his primary care provider for evaluation of a nonhealing sore on the left volar forearm of 6 weeks’ duration. The patient described the initial lesion as a red bump resembling a mosquito bite. Over 6 weeks the papule evolved into an indurated plaque with painless ulceration. The patient’s primary care provider had prescribed antibiotics for a presumed Staphylococcus aureus infection of the skin 5 weeks prior to presentation; however, the lesion continued to enlarge in size, resulting in referral to our dermatology clinic.
Skin examination revealed a solitary, 4-cm, painless, ulcerated plaque on the left volar forearm (Figure 1). No lymphadenopathy was noted. The patient reported that he had returned from a mission trip to rural Costa Rica 2 weeks prior to the appearance of the lesion. His medical history was otherwise unremarkable and his vital signs were within normal limits. Our initial differential diagnosis included pyoderma gangrenosum, Sweet syndrome, cutaneous leishmaniasis, and an insect bite.
Figure 1. Nonhealing, pink, crusted plaque with central ulceration on the left volar forearm.
Histopathologic study of a 5-mm punch biopsy specimen from the lesion showed a dense nodular and diffuse lymphohistiocytic infiltrate containing foci of suppuration. Within these suppurative foci were histiocytes parasitized by intracellular organisms that appeared to be of uniform size and shape on Giemsa staining, all of which are considered to be pathognomonic features of cutaneous leishmaniasis6 (Figures 2 and 3). The dermatopathologist’s diagnosis of cutaneous leishmaniasis was confirmed by the Centers for Disease Control and Prevention. The species was identified by polymerase chain reaction (PCR) as L panamensis.
The patient was treated with intravenous sodium stibogluconate 20 mg/kg for 20 consecutive days as recommended by expert consensus. The decision to treat a frequently self-limited cutaneous lesion with a highly toxic systemic drug was based on the small but real risk of metastatic mucosal lesions, which is caused by the Viannia subgenus, including L panamensis. Of note, sodium stibogluconate and other antimony drugs are not sold in the United States. Sodium stibogluconate is approved by the US Food and Drug Administration to be distributed by the Centers for Disease Control and Prevention under a protocol requiring baseline and weekly electrocardiograms and monitoring of patients’ creatinine, transaminase, lipase, amylase, and complete blood count levels.7 Our patient tolerated treatment but experienced mild to moderate flulike symptoms. The patient experienced no remarkable sequelae other than scarring in the affected area. He was warned to notify his health care providers of any persistent nasal symptoms, including nasal stuffiness, mucosal bleeding, and increased secretions, heralding the possibility of mucosal metastasis.
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Figure 2. Dense nodular and diffuse lymphohistiocytic infiltrate containing foci of suppuration (H&E, original magnification ×10). | Figure 3. Histiocytes parasitized by intracellular organisms of uniform shape and size on Giemsa staining (original magnification ×1000). |
Comment
The true incidence of cutaneous leishmaniasis in American travelers returning from Mexico and South and Central Americas is not known. The best incidence estimates are based on the number of physician requests for sodium stibogluconate and travel surveillance data collected by the Centers for Disease Control and Prevention. One study estimated the incidence of cutaneous leishmaniasis in Americans to be 1 case per every 100,000 travelers to Mexico.9 Data on the incidence of cutaneous leishmaniasis in American travelers seen in travel clinics for skin lesions gives a different perspective.10 Leishmaniasis is one of the most common dermatologic diseases seen in patients (European, North American, and other) returning from South America, accounting for 143 of every 1000 patients diagnosed with a skin disease acquired in South America.
