Final answer:
Vitiligo is the condition in which there is a deficiency of skin pigmentation in patches due to loss of melanin production by melanocytes, possibly due to an autoimmune reaction. It is not to be confused with albinism, which is a genetic disorder affecting melanin production completely or partially. Other skin conditions like melanoma, psoriasis, and eczema have different pathologies.
Step-by-step explanation:
The deficiency of skin pigmentation, especially in patches, is known as vitiligo. This condition is characterized by the depigmentation of the skin, resulting in lighter colored patches that are more noticeable on darker skin. In vitiligo, melanocytes in certain areas of the skin lose their ability to produce melanin, possibly due to an autoimmune reaction, leading to a loss of color. Unlike albinism, which is a genetic disorder that completely or partially affects the production of melanin in the skin, hair, and eyes, vitiligo typically presents as patches of depigmentation. Other conditions mentioned, such as melanoma, psoriasis, and eczema, involve different pathologies and symptoms. Melanoma is a type of skin cancer, psoriasis is a chronic autoimmune condition that causes rapid skin cell production resulting in scaling on the skin's surface, and eczema is an inflammatory condition characterized by red, itchy, and swollen skin.