Precocious sexual development in girls
In girls who present with signs of precocious sexual maturation below the age of 8 years, the direction of investigation can be helped by noting whether or not breast development is present. Breast development signifies oestrogen secretion which is either due to ovarian autonomy (ovarian cyst) or McCune Albright's Syndrome (gonadotropin dependant puberty) or initiation of the normal pubertal mechanism (gonadotropin dependant puberty). In girls this is most often idiopathic but can arise from CNS disturbance such as intracranial lesions, hydrocephaly and head injuries.
Signs of sexual development (pubic and axillary hair, rapid growth, acne and body odour) without breast enlargement is usually due to adrenal androgens. The commonest cause is simple precocious adrenarche, a normal variant occurring between the ages of 6 and 7 years of age. But adrenal pathology needs to be excluded (tumours, late onset congenital adrenal hyperplasia etc).