Excessive body hair growth
"Hirsutism" is defined as the growth of hair in a woman on the face and body which appears in the same pattern and with the same temporal development as in men. This form of hair growth is dependent on stimulation by androgens. It differs significantly from "hypertrichosis" which is an uniform growth of hair over the entire body and which develops either as part of a congenital or metabolic disorder (eg anorexia nervosa and hypothyroidism) or in response to non-hormonal drugs (eg cyclosporin and minoxidil). There is, therefore, more than just a semantic difference, for although the terms are merely Latin and Greek for excessive hair growth, the use of one term rather than the other has aetiological implications.
The presence of hirsutism can only be determined by clinical examination of the pattern and timing of the hair growth. The natural development of androgenic body hair begins at puberty with a conversion of vellus to terminal hairs in the pubic area followed by the axillae after an interval of about two years. Facial hair appears at the same time as axillary hair in boys. Terminal hairs start at the corners of the lips and spread over the upper lip before appearing on the chin and then cheeks. An orderly sequence of hair conversion follows on the body: the lower legs, thighs, forearms, abdomen, buttocks, chest, back, upper arms and shoulders (Reynolds 1951).
Hypertrichosis differs firstly in having an uniform distribution of hair over the entire body and secondly as the hair shafts themselves have an homogeneous silky smooth form unlike the thick, coarse and curly hair shafts seen in hirsutism.
Investigation strategy for hirsuties
A full clinical evaluation should be made for the pattern of development of hirsuties and the presence of systemic virilism (ie cliteromegaly, increased muscle bulk, deep voice, scalp balding, amenorrhoea etc). In the absence of features of systemic virilism, then a measurement of plasma testosterone is a suitable screening test for serious endocrine disturbance. Further evaluation is required if the testosterone is > 4 nmol/L in premenopausal or > 2 nmol/L in post-menopausal women (Barth et al 2010).
Other investigations to evaluate the degree of insulin resistance such as fasting glucose and lipid profile might also be appropriate.
- J.H.Barth, H.P.Field, E.Yasmin, A.H.Balen. Defining hyperandrogenism in
polycystic ovary syndrome: measurement of testosterone and androstenedione by
liquid chromatography-tandem mass spectrometry and analysis by receiver
operator characteristic (ROC) plots. Eur J Endocrinol 2010;162:611-5.
- E.L.Reynolds. The appearance of adult patterns of body hair in man. Ann NY Acad Sci 1951;53:576-584.