What condition is indicated by the absence of hair from areas where it normally grows?

Alopecia is the medical term used to describe the condition characterized by hair loss from areas where hair typically grows. This can manifest in various forms, including localized patches of hair loss (alopecia areata) or more extensive types, such as totalis, where all scalp hair is lost, or universalis, where hair loss occurs over the entire body. The absence of hair can result from various factors, including genetic predisposition, autoimmune responses, hormonal changes, or certain medical conditions.

In contrast, gangrene refers to tissue death due to a lack of blood supply, typically causing discoloration and necrosis rather than hair loss. A fissure is a split or crack in a bodily structure, often associated with skin or mucous membranes, without any direct relation to hair. A wheal is a raised, itchy area on the skin, often associated with allergic reactions or insect bites, and again does not pertain to hair loss. Understanding these distinctions clarifies why alopecia is the accurate answer in the context of hair absence.