Many people pluck or wax eyebrows for aesthetic purposes, but for some, eyebrow hair loss is an unwelcome problem. There are various reasons for the loss of eyebrow hair, some are temporary and treatable while others are permanent.
The body attacks tissue by mistake, making alopecia areata an autoimmune disease. About 1 percent of the population experiences the patchy hair loss anywhere on the body, and most eventually resume hair growth, according to the American Osteopathic College of Dermatology.
Eyebrow hair falls out in response to severe inflammation, itching and scratching associated with psoriasis or atopic dermatitis and eczema, according to Dermadoctor.com.
Cancer may push out hair in areas it's taking over. Medication, such as chemotherapy, will cause hair to stop growing as it affects the production of many cells, not just the cancerous ones.
Androgenic alopecia causes "balding" and can lead to thinning eyebrows over time. It's caused by the testosterone-like androgen hormone. Pregnancy, thyroid disease and birth control pills can also slow hair growth according to Dermadoctor.com.
Side effects of some antidepressants and emotional stabilizers, such as Prozac, may result in temporary hair loss. According to Dermadoctor.com, usually, as soon as the medication is out of the body, one will notice eyebrows growing fuller.
Routine plucking or waxing can destroy the hair follicle and lead to permanent loss. Trichotillomania, a diagnosed habit of pulling out body hair may cause permanent damage to the sensitive follicles.