Post-kala-azar dermal leishmaniasis (PKDL) is a complication of visceral leishmaniasis (VL); it is characterised by a macular, maculopapular, and nodular rash in a patient who has recovered from VL and who is otherwise well. The rash usually starts around the mouth from where it spreads to other parts of the body depending on severity. Post-kala-azar dermal leishmaniasis (also known as "Post-kala-azar dermatosis") found mainly on the face, arms, and upper part of the trunk. It occurs years (in the Indian variation) or a few months(in the African strain) after the successful treatment of visceral leishmaniasis. It is mainly seen in Sudan and India where it follows treated VL in 50% and 5-10% of cases, respectively. Thus, it is largely restricted to areas where Leishmania donovani is the causative parasite. The interval at which PKDL follows VL is 0–6 months in Sudan and 2–3 years in India. PKDL probably has an important role in interepidemic periods of VL, acting as a reservoir for parasites. PKDL was first identified by Sir Upendranath Brahmachari, who initially called it dermal leishmanoid. He published his observations in the Indian Medical Gazette in 1922. Mechanism
The cause of PKDL is uncertain. Possibilities may include use of antimonial drugs, sunburn, reinfection with kala-azar, memory T cell responses failing in certain organs; and genetic susceptibility.There is increasing evidence that the pathogenesis is largely immunologically mediated; high concentrations of interleukin 10 in the peripheral blood of VL patients predict the development of PKDL.
Praziquantel (PZQ), sold under the brandname Biltricide among others, is a medication used to treat a number of types of parasitic worm infections in mammals, birds, amphibians, reptiles, and fish. In humans specifically, it is used to treat schistosomiasis, clonorchiasis, opisthorchiasis, tapeworm infections, cysticercosis, hydatid disease, and other fluke infections. It should not be used for worm infections of the eye. It is taken by mouth.Side effects in humans may include poor coordination, abdominal pain, vomiting, headache, and allergic reactions. While it may be used during pregnancy, it is not recommended for use during breastfeeding. Praziquantel is in the anthelmintic class of medications. It works partly by affecting the function of the worms sucker.Praziquantel was approved for medical use in the United States in 1982. It is on the World Health Organizations List of Essential Medicines. Medical uses
Praziquantel is used to treat diseases caused by infection with several types of internal/gastrointestinal, and external parasites, including:

Hydatid disease caused by infection of various organs with larval stages of tapeworms of the genus Echinococcus
Cysticercosis caused by infection of the brain and/or muscles with the eggs and larvae of the pork tapeworm Taenia solium (though it has been judged less effective than albendazole in treatment of neurocysticercosis)
In dogs and cats, whose gastrointestinal tracts are infected with the tapeworms Dipylidium caninum or Taenia taeniaeformis, respectively; praziquantel is also often used in fixed combination with pyrantel embonate against the roundworms (ascarids): Toxocara cati and Toxascaris leonina. Praziquantel is also effective against Echinococcus multilocularis.