American actor Lili Reinhart revealed that she had an alopecia diagnosis, according to the Hollywood Reporter. Recently, the `Riverdale` star took to TikTok to post a video of her undergoing red light therapy, and wrote in the clip, "Was just diagnosed with alopecia in the midst of a major depressive episode."

Alopecia develops when the "immune system attacks hair follicles and causes hair loss," according to the National Institute of Health.