What is the reason behind turning the skin black during kala azar or dum dum fever?

Kala azar, or dum dum fever, is caused by the Leishmania parasite, which is transmitted through the bite of infected sandflies. The condition leads to severe anemia and can cause the skin to darken due to a combination of factors, including the body's response to infection, the breakdown of red blood cells, and the accumulation of melanin. Additionally, the disease can affect the liver and spleen, leading to changes in skin pigmentation. This skin discoloration is often referred to as "hyperpigmentation" and is a notable symptom of the disease.