Leishmaniasis outbreak: North texas cases signal endemic spread

Nov 01, 2007, 4:00am

Dermatologists have long known to suspect leishmaniasis in patients in South Texas, near the Mexican border. Elsewhere in the United States, dermatologists should suspect that persistent sores in patients who have traveled to South or Central America, Mexico or the Middle East could also be caused by the protozoan Leishmania.

Key Points

Dermatologists in North Texas are now diagnosing leishmaniasis in patients who have not traveled to recognized endemic areas, which suggests the geographic range of the infectious skin disease may be spreading.

Kent Aftergut, M.D., assistant clinical instructor of dermatology at the University of Texas Southwestern and in private practice at Methodist Charlton Medical Center, Dallas, says he and colleagues in the Dallas-Fort Worth area have diagnosed nine leishmaniasis cases in patients from the Dallas area who have not traveled outside North Texas.

"Clearly, this is a condition that is moving to the north - we are talking about 400 to 500 miles north of where the previous diagnosed cases have been," Dr. Aftergut says. "Dermatologists should keep leishmaniasis in the differential - especially if patients being treated for staph infections have not improved with short courses of antibiotics."

Telltale signs

Leishmaniasis lesions usually appear as persistent, slowly growing ulcerated nodules. All of the cases reported in Texas have been caused by Leishmania mexicana, and present strictly as cutaneous manifestations of the disease without spreading throughout the body.

Some leishmaniasis forms present a clear danger, says Scott Alan Norton, M.D., M.P.H., associate professor of dermatology, Uniformed Services University of the Health Sciences, Bethesda, Md.

"Leishmaniasis can be severely disfiguring, severely debilitating and lethal. The form of infection in Texas, however, is usually confined to the skin and, although it might be unsightly, it is not life-threatening," he tells Dermatology Times.

Diagnosis

Dermatologists cannot confirm the diagnosis of leishmaniasis with routine cultures, Dr. Aftergut says.

"Special cultures have to be done to confirm the diagnosis," he says. "The Centers for Disease Control and Prevention (CDC) will send you all that you need to culture the organism. The CDC wants doctors to report it, so they can track the spread of leishmaniasis."

Treatment

Leishmaniasis treatment is difficult, Dr. Aftergut says. The most effective treatment (not approved by the Food and Drug Administration to treat leishmaniasis), he says, is intravenous sodium stibogluconate, a sometimes toxic medication.

"We do not use sodium stibogluconate unless a patient has a very bad case," he says.

Other treatments that have been shown to have off-label efficacy include the antifungal amphotericin, but that, too, has undesirable side effects, Dr. Aftergut says.

Not treating patients is an option; however, leishmaniasis can be very painful and lesions tend to last six to 12 months in patients with normal immune systems. Dermatologists can also use surgery or excision to treat the lesions.

"Other antifungal medicines such as fluconazole seem to have some activity," Dr. Aftergut says. "We had a patient that had two very painful spots, and we had given him the option of not treating, but he did not like that idea at all. So, we did small excisions of his two lesions and closed them with 'purse-string' closures. He then took oral fluconazole for two months and is cured."