Alopecia areata causes unpredictable hair loss in 2% of population

Alopecia areata is an unpredictable autoimmune disease that affects approximately 2% of the global population. According to dermatologist Enilde Borges Costa of the Brazilian Society of Dermatology (SBD), the condition occurs when the body attacks hair follicles, preventing healthy hair growth.

The disease can manifest in three ways: localized hair loss in small areas of the scalp, total alopecia areata affecting the entire scalp, or universal alopecia areata, which results in the loss of all body hair. Episodes are often cyclical, alternating between hair loss and regrowth.

Diagnosis is conducted through clinical examination in a medical office, as there are currently no laboratory or imaging tests to confirm the condition. Because the disease does not cause lesions or scarring, doctors often use simple physical tests, such as checking for hair that pulls out easily or observing loss in eyebrows, eyelashes, and beards. While the condition has a genetic component and can be triggered by immune system changes, such as infections, it is not classified as a purely psychological illness.