By Adrienne Stinson Reviewed by Cynthia Cobb, APRN Many factors can cause eyebrow hair loss, including hormonal imbalances, diet, and some skin conditions. Determining the cause of eyebrow hair loss can help a person find the best treatment. Eyebrow hair loss, the medical name for which is eyebrow hypotrichosis, or eyebrow madarosis, can cause a person to notice thinning hair or missing patches of hair in...