Why do eyebrows continue to grow when you go bald?

The common variety of balding in males is due to the effect of male hormone testosterone, hair on the scalp is especially sensitive to testosterone, after puberty mature males normally have loss of hair over the temples. Which probably makes them look sexy eg.Bruce Willis. So balding is an extreme form of hormone sensitivity.The hair over the eyebrows is not sensitive to testosterone so it is not lost.

But in a condition called alopecia totalis hair is lost over the eyebrows too, but his is due to destruction of hair follicles by a skin disease.In hypothyroidism a condition where thyroid function is reduced hair over the eyebrows is lost.