The outer third of the eyebrows (Hertogh’s sign) may be lost in a number of disorders.
Causes of Hertogh’s sign:
(1) hypothyroidism
(2) hypogonadism
(3) other endocrinopathies
(4) autonomic dysfunction
(5) diphtheria
(6) neurodermatitis
(7) scleroderma
Differential diagnosis:
(1) physical plucking at eyebrow hairs
(2) alopecia
(3) facial burn
