Leishmaniasis natural history
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Alejandro Lemor, M.D. [2]
Overview
The term leishmaniasis encompasses multiple clinical syndromes (cutaneous, mucosal, and visceral forms), which result from infection of macrophages in the dermis, in the naso-oropharyngeal mucosa, and throughout the reticuloendothelial system, respectively. For all three forms, the infection can range from asymptomatic to severe. Cutaneous and mucosal leishmaniasis can cause substantial morbidity, whereas visceral leishmaniasis can be life threatening.
Natural History
Cutaneous Leishmaniasis
- This is the most common form of leishmaniasis, both in general and in U.S. travelers.
- Unless otherwise specified, cutaneous leishmaniasis refers to localized cutaneous leishmaniasis, rather than to much less common forms, such as diffuse cutaneous leishmaniasis and disseminated cutaneous leishmaniasis.
- In general, cutaneous leishmaniasis causes skin lesions, which can persist for months, sometimes years.
- The skin lesions usually develop within several weeks or months after the exposure but occasionally first appear years later (for example, in the context of trauma or immunosuppression).
- The lesions typically evolve from papules to nodular plaques to ulcerative lesions, with a raised border and central depression, which can be covered by scab or crust; some lesions persist as nodules.
- The lesions usually are painless but can be painful, especially if ulcerative lesions become infected with bacteria or if the lesions are near a joint.
- The healing process typically results in atrophic scarring.
- Even patients with localized cutaneous leishmaniasis quite commonly develop more than one primary lesion (on the same or different parts of the body), satellite lesions, regional lymphadenopathy (occasionally bubonic), and/or nodular lymphangitis (sporotrichoid-like subcutaneous nodules).
- Sometimes lymphadenopathy is noticed first, before skin lesions develop.
Mucosal Leishmaniasis
- Mucosal leishmaniasis (also called espundia) traditionally refers to a metastatic sequela of New World cutaneous infection, which results from dissemination of parasites from the skin to the naso-oropharyngeal mucosa.
- Adequate systemic treatment of cutaneous leishmaniasis caused by these species is thought to reduce the risk for mucosal disease, but some risk may remain.
- The magnitudes and determinants (parasite and host factors) of the risks for mucosal dissemination and for mucosal disease per se are poorly understood; even for the same species (for example, L. [V.] braziliensis), the risks appear to vary among geographic regions in the Americas.
- Mucosal leishmaniasis usually becomes clinically evident within several years (sometimes as long as decades) of the original cutaneous lesions, which typically were not treated at all or were treated suboptimally. However, mucosal and skin lesions may be noted concomitantly (mucocutaneous leishmaniasis), and some patients had subclinical cutaneous infection.
- The initial manifestations of mucosal leishmaniasis usually are persistent, unusual nasal symptoms (such as stuffiness or bleeding), although oral or pharyngeal symptoms sometimes are noticed first.
- If untreated, the disease can progress to ulcerative destruction of the naso-oropharyngeal mucosa (such as perforation of the nasal septum).
Complications
- Deadly infections due to immune system damage
- Disfigurement of the face
- Bleeding (hemorrhage)
Prognosis
The skin sores of cutaneous leishmaniasis will heal on their own, but this can take months or even years. The sores can leave ugly scars. If not treated, infection that started in the skin rarely spreads to the nose or mouth and causes sores there (mucosal leishmaniasis). This can happen with some of the types of the parasite found in Central and South America. Mucosal leishmaniasis might not be noticed until years after the original skin sores healed. The best way to prevent mucosal leishmaniasis is to treat the cutaneous infection before it spreads.
- If not treated, visceral leishmaniasis can cause death.
- Some people have had cutaneous leishmaniasis more than once.