Hirsutism and virilization reflect excess androgen production in a genetically female individual, and are characterized by excess male-pattern hair growth.
Both hirsutism and virilization may or may not be associated with weight gain, acne, and even male pattern balding.
With virilization, however, females may also have a deepened voice and clitoromegaly, which are not seen with hirsutism.
The excess androgens can come either from the ovary - and the main androgen here is testosterone - or the adrenal glands - which mainly secrete an androgen called dehydroepiandrosterone sulphate.
Ok, now excess hair growth can be quantified using the Ferriman-Gallwey score. This score requires assessing the amount of hair present in nine body areas: the upper lip, chin, chest, upper and lower back, upper and lower abdomen, upper arms, and thighs.
Hair growth in each of the nine areas are graded from 0, meaning no terminal hair growth, to 4, meaning extensive terminal hair growth.
Ethnicity must be taken into account when interpreting the score, as the normal amount of body hair can vary between ethnic groups.
So, for females of caucasian and african descent, scores between 8 and 15 indicate mild hirsutism, 16 to 25 indicate moderate hirsutism, and scores greater than 25 indicate severe hirsutism.
For females of Asian descent, who have naturally sparse body hair, a score greater than 2 is sufficient to establish the presence of hirsutism, whereas for females of Mediterranean, Hispanic, and Middle Eastern descent, who naturally have more body hair, only a score higher than 10 is considered abnormal.
Given this variation, the most important consideration is not necessarily the amount of body hair a female has, but rather if the pattern of hair growth has changed, or the rate of growth has increased.