Eyebrow hair loss

  There are many reasons for eyebrow hair loss. Use of eyebrow pencil excessively can hamper the growth of hair and make it fall. Excessive plucking, rubbing eyebrow from  habit can also make eyebrow hair fall out.
Eyebrow hair can also thin with ageing, just as scalp hair can.
In Certain medical conditions there is loss of eye brow hair also along with scalp hair like in hypothyroid or endocrine imbalances. Alopecia Areata, is autoimmune conditions where hair loss is actually a case of mistaken identity. Your body's immune system mistakenly thinks that the hair follicle is bacteria and tries to protect the body from it by attacking it. Unfortunately, when this happens, you lose the hair. Scientists are still unsure of why this happens or even why it happens to one person and not to the next.
Eczema can also sometimes be associated with loss of eyebrows, often from scratching. Some medications may cause loss of eyebrows and scalp hair.

Homeopathy medicines have good results in these cases.