Hirsutism is a condition seen in women that is associated with development of androgen-dependent terminal hair (coarse, pigmented) following a male-pattern distribution (face, chest, abdomen, back).
A comprehensive history and physical exam can narrow the diagnosis of the underlying condition.[1]Martin KA, Anderson RR, Chang RJ, et al. Evaluation and treatment of hirsutism in premenopausal women: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2018 Apr 1;103(4):1233-57.
https://academic.oup.com/jcem/article/103/4/1233/4924418
http://www.ncbi.nlm.nih.gov/pubmed/29522147?tool=bestpractice.com
Hormonal studies and imaging are typically used for patients with moderate to severe hirsutism.
Women with idiopathic hirsutism have normal androgen levels and regular menstrual cycles. It is a diagnosis of exclusion and is due to increased local sensitivity to androgens or increased local conversion of testosterone to dihydrotestosterone.
The most common cause of hirsutism is polycystic ovary syndrome (PCOS).[2]Elliott J, Liu K, Motan T. Guideline no. 444: hirsutism: evaluation and treatment. J Obstet Gynaecol Can. 2023 Dec;45(12):102272.
http://www.ncbi.nlm.nih.gov/pubmed/38049282?tool=bestpractice.com
Hyperandrogenemia is present in 60% to 80% of women with PCOS.[3]Azziz R, Carmina E, Dewailly D, et al. Positions statement: criteria for defining polycystic ovary syndrome as a predominantly hyperandrogenic syndrome: an Androgen Excess Society guideline. J Clin Endocrinol Metab. 2006 Nov;91(11):4237-45.
https://academic.oup.com/jcem/article-abstract/91/11/4237/2656314
http://www.ncbi.nlm.nih.gov/pubmed/16940456?tool=bestpractice.com
Very high levels of total testosterone concentration may be caused by an ovarian or adrenal tumor. Virilization (e.g., male-pattern alopecia, deepening voice, changes in libido, clitoromegaly, increased muscle bulk) that appears over a short period of time should arouse suspicion regarding a tumor of either adrenal or ovarian origin.
Pathophysiology
Hair in different areas of the body demonstrates varying levels of androgen sensitivity, depending mostly on local sensitivity of androgen receptors and 5-alpha-reductase activity levels. Terminal hair, also known as sexual hair, is dependent on androgens for development and maintenance.[4]Deplewski D, Rosenfield RL. Role of hormones in pilosebaceous unit development. Endocr Rev. 2000 Aug;21(4):363-92.
http://edrv.endojournals.org/cgi/content/full/21/4/363
http://www.ncbi.nlm.nih.gov/pubmed/10950157?tool=bestpractice.com
Hair response to androgens varies from person to person and includes increase in follicle size, fiber diameter, and the amount of time spent in anagen (the growth-cycle phase of a hair follicle).[5]Rosenfield RL. Clinical practice. Hirsutism. N Engl J Med. 2005 Dec 15;353(24):2578-88.
http://www.ncbi.nlm.nih.gov/pubmed/16354894?tool=bestpractice.com
[6]Messenger AG. The control of hair growth: an overview. J Invest Dermatol. 1993 Jul;101(suppl 1):4S-9S.
http://www.ncbi.nlm.nih.gov/pubmed/8326154?tool=bestpractice.com
Around 70% to 80% of women with androgen excess manifest hirsutism.[2]Elliott J, Liu K, Motan T. Guideline no. 444: hirsutism: evaluation and treatment. J Obstet Gynaecol Can. 2023 Dec;45(12):102272.
http://www.ncbi.nlm.nih.gov/pubmed/38049282?tool=bestpractice.com
[7]Azziz R. The evaluation and management of hirsutism. Obstet Gynecol. 2003 May;101(5 Pt 1):995-1007.
http://www.ncbi.nlm.nih.gov/pubmed/12738163?tool=bestpractice.com
Excessive sexual hair may be accompanied by signs of virilization. When present, virilization indicates an underlying condition associated with moderately to severely elevated androgen levels (such as an androgen-secreting tumor).[2]Elliott J, Liu K, Motan T. Guideline no. 444: hirsutism: evaluation and treatment. J Obstet Gynaecol Can. 2023 Dec;45(12):102272.
http://www.ncbi.nlm.nih.gov/pubmed/38049282?tool=bestpractice.com
Epidemiology
The extent of terminal hair varies by ethnic background and the method used to evaluate it.[7]Azziz R. The evaluation and management of hirsutism. Obstet Gynecol. 2003 May;101(5 Pt 1):995-1007.
http://www.ncbi.nlm.nih.gov/pubmed/12738163?tool=bestpractice.com
Women of Asian ethnicity have less body hair compared with southern European women. Among white and black American women, the prevalence of hirsutism, as assessed by a standard score, is 20%.[8]DeUgarte CM, Woods KS, Bartolucci AA, et al. Degree of facial and body terminal hair growth in unselected black and white women: toward a populational definition of hirsutism. J Clin Endocrinol Metab. 2006 Apr;91(4):1345-50.
https://www.doi.org/10.1210/jc.2004-2301
http://www.ncbi.nlm.nih.gov/pubmed/16449347?tool=bestpractice.com
The prevalence of hirsutism is approximately 10% in most populations; however, women of Thai and Chinese ethnicities present hirsutism with a prevalence of 2%.[9]Escobar-Morreale HF, Carmina E, Dewailly D, et al. Epidemiology, diagnosis and management of hirsutism: a consensus statement by the Androgen Excess and Polycystic Ovary Syndrome Society. Hum Reprod Update. 2012 Mar-Apr;18(2):146-70.
http://www.ncbi.nlm.nih.gov/pubmed/22064667?tool=bestpractice.com
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