Leishmaniasis is a protozoan parasitic disease transmitted by the bite of a sand fly. Depending on the parasite (sub)species and the immune status of the host, leishmaniasis presents as cutaneous disease (CL, ~90% of cases, presentation ranges between localized single lesions, and diffuce or recurrent forms), mucocutaneous leishmaniasis (MCL, mainly in the “new world,” inefficient prior treatment or untreated primary CL), and visceral leishmaniasis. Without treatment, VL is life-threatening.
Therapy should be based on disease presentation (CL vs MCL or VL), and the parasite subspecies—thus, parasite determination via PCR is important for the treatment decision. The immune status of the host and regional parasite resistance to certain drugs need to be considered as well. A lack of controlled studies make the choice of treatment complicated.
Systemic Versus Topical Treatment
To decide between systemic or topical treatment, clinical severity of disease needs to be determined. To this aim, “uncomplicated/non complex” lesions are differentiated from “complicated/complex” lesions.
Patients with complex lesions should preferentially receive systemic therapy, if possible. Complex lesions are defined as lesions which are larger than 4 cm, as lesions on patients with more than 3 lesions, and those with lesions in cosmetically or functionally important sites such as joints, face, genitalia, and fingers/toes. The same applies to diffuse or progressive leishmaniasis, recurrent lesions, lesions with lymphadenopathy or satellites, and sporotrichoid lesions. In line, patients with known immunosuppression (which may lead to reactivation of the parasite) due to, eg, HIV, cancer, or anti-TNFa treatment, as well as all cases with MCL and VL should receive systemic therapy.
As a rule, leishmaniasis acquired in countries in the New World tend to be more severe and progressive; they can progress into MCL, thus necessitate systemic therapy. The only exeptions are infections with L. mexicana, which show little to no tendency to progress; here, topical treatment can be considered.
Pregnancy and other reasons may favor local treatment because of the toxicity of the drugs.
For systemic treatment, a variety of drugs are available, only very few have FDA approval. Toxicity is high and needs to be considered. In addition, the choice of treatment depends on the parasite (sub)species; contacting a specialist to discuss the best choice may be helpful and is most often possible, since the start of treatment is not time-sensitive.
Clinical observation in immunocompetent hosts is reasonable in uncomplicated lesions (with no risk for MCL) which show the tendency for spontaneous healing. If spontaneous healing does not occur in a time frame of ~2 months, treatment needs to be reconsidered. The benefits of treatment are accelerated healing, fewer recurrences, and less scarring.
In some cases, combinations of topical therapy with procedures can ...