Which dermatological condition is marked by an autoimmune response leading to hair loss?

Alopecia areata is an autoimmune condition characterized by sudden hair loss that can occur in patches or in total. It results from the immune system mistakenly attacking hair follicles, causing the hair to fall out. The mechanism behind this is not fully understood, but it involves an immune-mediated process in which T lymphocytes infiltrate the hair follicles, leading to hair loss. This distinct feature of an autoimmune response sets alopecia areata apart from other forms of hair loss.

In contrast, androgenetic alopecia is primarily a genetic condition associated with hormonal changes, primarily dihydrotestosterone (DHT), playing a significant role in this type of hair loss, which typically presents as gradual thinning rather than patchy bald spots. Telogen effluvium is usually a temporary form of hair loss that occurs due to a shift in the hair growth cycle, often triggered by stress, illness, or hormonal changes. Scarring alopecia, while also leading to hair loss, involves inflammation causing permanent damage to the hair follicles, but it is not classified as an autoimmune process in the same manner as alopecia areata. Thus, autoimmune response specifically points to alopecia areata as the correct answer.