Cutaneous leishmaniasis (Aleppo boil): successful treatment with topical paromomycin (Humatin®)

ARTICLE

A 25-year-old German female presented with an indurated, 1.1 x 2.0 cm nodule on the left cheek (Fig. 1). The lesion was ulcerated and covered with a thick yellowish crust. Multiple additional nodules were seen in a sporotrichoid distribution on the right arm. The lesions arose 2 weeks before the initial appointment. Interestingly, the patient, who had just returned from an archeological expedition in Syria (Aleppo province), reported that similar lesions had arisen in several other participants of the expedition.

Histologic findings

In Giemsa-stained tissue smears taken from the edge of the cheek ulcer as well as in a biopsy taken from a nodule on the arm, typical Leishman-Donovan bodies were seen in the cytoplasm of macrophages (Fig. 2).

Treatment and course

The patient was treated topically with 15% paromomycin sulfate (Humatin^®) in petrolatum, which was applied twice daily under occlusion. Although the patient developed contact dermatitis caused by the wound dressing (colophony resin), the lesions became less infiltrated and smaller in size within the first week of treatment. Open application of the paromomycin ointment was continued for another 3 weeks and then stopped, since the lesions were flat and without any signs of activity (Fig. 3). Follow up examinations confirmed the healing of the infection.

Discussion

Leishmaniasis is caused by an intracellular protozoan parasite, which is transmitted by bites of sandflies of the genus Phlebotomus. Clinical features of the disease are determined by the species of Leishmania as well as the immune response of the patients. Leishmaniasis may affect skin, mucous membranes or even visceral organs.

Old World cutaneous leishmaniasis, also known as oriental sore, Aleppo boil, Baghdad or Lahore sore is a chronic but usually self-limiting skin infection. As indicated by the designations, the disease is endemic in countries of the middle east. The morphologically identical species L. tropica and L. major are the infectious agents in this geographical region. New World cutaneous leishmaniasis, found in Latin America, has similar clinical features, but is caused by different Leishmania species.

Following an incubation period of a few weeks (infrequently up to 2 years), furuncle-like nodules arise at inoculation sites. Induration of the flat ulcerated lesions is a characteristic feature. In immunocompetent hosts, the disease is self-limiting. After 2-6 months the lesions heal spontaneously and leave lifelong immunity [1]. Clinical diagnosis can be confirmed by tissue smears or biopsies with the microscopic demonstration of Leishman Donovan bodies in histiocytes. Although CL is a self-limiting disease which does not necessarily require specific therapy, facial lesions should be treated to avoid or to minimize possible scarring.

A wide range of treatment modalities for CL have been recommended including indigenous plants, hyperthermia or cryotherapy, topical petroleum by-products, antibiotics or antimalarials, topical or systemic ketoconazole or itraconazole, systemic allopurinol, meglumine antimonate and gamma interferon [2-9]. Intralesional injection of sodium stibogluconate antimony has been recommended as therapy of choice because of its efficacy, although this procedure is often painful [10].

Recently, the therapeutic efficacy of a new treatment modality for Old World CL, topical application of an ointment containing paromomycin sulfate and methylbenzethonium chloride has been confirmed in a double blind study [11, 12]. This combination seems to be also effective in the treatment of New World CL [13-15], although in mice infected with L. mexicana or L. panamensis this combination failed to cure the lesions [16]. In some areas infested with Old World leishmaniasis a preparation containing 15% paromomycin sulfate and 5% methylbenzethonium chloride is commercially available.

Paromomycin (Humatin^®) is an aminogylcoside antibiotic, which is commonly used for reduction of normal and pathogenic microorganisms of the gastrointestinal tract. Additionally, the substance is effective in the treatment of intestinal amebiasis and various tapeworms. Methylbenzethonium chloride is a quaternary ammonium compound which acts as a detergent as well as an antiseptic and desinfectant.

Since we could not obtain this preparation quickly, we administered 15% paromomycin sulfate in petrolatum, which was readily available. The impressive improvement of the lesions within 1 week and cure after 4 weeks of treatment suggests that this monotherapy was effective. Therefore, topical paramomycin monotherapy or combined with urea [11] may be recommended as an inexpensive and effective treatment with minimum or no side effects for cases in which a commercial preparation is not available. It should be noted that, local treatment with paromomycin should be carried out for at least 4 weeks or until the lesions clear, since a recent study [17] failed to detect a benefit after 2 weeks of treatment.

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