infectious diseases
Leishmaniasis
Symptoms and Signs of Leishmaniasis
Incutaneous leishmaniasis,a well-demarcated skin lesion develops at the site of a sand fly bite, usually within several weeks to months. Multiple lesions may occur after multiple infective bites or with metastatic spread. Their appearance varies. The initial lesion is often a papule that slowly enlarges, ulcerates centrally, and develops a raised, erythematous border where intracellular parasites are concentrated. Ulcers are typically painless and cause no systemic symptoms unless secondarily infected. Lesions heal spontaneously after several months but may persist for years. They leave a depressed, burn-like scar. The course depends on the infectingLeishmaniaspecies and the host’s immune status. a rare syndrome, results in widespread nodular skin lesions resembling those of Leprosy . It results from cell-mediated anergy to the organism. Mucosal leishmaniasisdue toL. braziliensisand related organisms typically starts with one or more primary cutaneous ulcers. Spread to the mucosa via lymphatics and the bloodstream probably occurs early in infection. The skin lesions heal spontaneously; but progressive mucosal lesions may not become apparent for months to years. Typically, patients have nasal stuffiness, discharge, and pain. Over time, the infection may progress, resulting in gross mutilation of the nose, palate, oral pharynx, or face. Invisceral leishmaniasis,the clinical manifestations usually develop gradually over weeks to months after inoculation of the parasite but can be acute. Irregular fever, hepatosplenomegaly, pancytopenia, and polyclonal hypergammaglobulinemia with a reversedalbumin:globulin ratio occur. In some patients, there are twice-daily temperature spikes. Cutaneous skin lesions rarely occur. Emaciation and death occur within months to years in patients with progressive infections. Those with asymptomatic, self-resolving infections and survivors (after successful treatment) are resistant to further attacks unless cell-mediated immunity is impaired (eg, by AIDS). Relapse may occur years after initial infection. Post kala-azar dermal leishmaniasis (PKDL)may develop after treatment for visceral leishmaniasis in patients in the Sudan and India. It is characterized by flat or nodular cutaneous lesions that contain many parasites. In patients in the Sudan, these lesions develop at the end of or within 6 months of therapy and spontaneously resolve a few months to a year later. In patients in India and adjacent countries, skin lesions typically develop 1 to 2 years after therapy ends and can last for many years. PKDL lesions are thought to be a reservoir for the spread of infection in these areas. 