Source — What Is Alopecia Universalis Causes And Treatments. What Is Alopecia Universalis? Alopecia universalis is the rarest form of alopecia areata. It strips every hair from the body - scalp (eyebrows)eyelashes, arms, legs, chest, and pubic area - in a complete, often permanent loss. The driver is autoimmune: the immune system's T cells mistake the hair follicles for foreign invaders and attack them, halting hair production entirely.
How It Differs From Other Forms Alopecia areata usually causes patchy bald spots, and alopecia totalis takes it further - total scalp hair loss. Alopecia universalis goes beyond, erasing all body hair. The condition affects an estimated 1 in 500,000 people globally. Researchers have not yet fully understood the mechanisms. What Happens in the Body Once triggered, the attack cycle becomes self-perpetuating, and inflammatory signals (interferon-gamma and interleukins) flood the hair follicle’s microenvironment. Patients typically experience sudden, rapid shedding over weeks or months. What Causes Alopecia Universalis?