What is vitiligo characterized by?

Vitiligo is characterized by localized loss of skin pigmentation. This condition arises when melanocytes, the cells responsible for producing melanin (the pigment that gives skin its color), are destroyed or stop functioning properly. This leads to lighter patches of skin that can appear on various parts of the body, creating a stark contrast with the surrounding skin areas. The exact cause of vitiligo is not fully understood, but it is often thought to be an autoimmune disorder where the body's immune system attacks its own melanocytes.

The other options describe different conditions. Localized excess of skin pigmentation relates to conditions like hyperpigmentation or age spots. Scaly red nodules on the skin may refer to psoriasis or other skin conditions, while blister-like clusters on the mucous membranes can be indicative of herpes simplex or other viral infections. Understanding vitiligo as specifically involving the loss of pigmentation is essential for recognizing it and differentiating it from other skin disorders.