What is the recommended workup for a female patient presenting with hirsutism (excessive hair growth)?

Hirsutism Workup

Initial Clinical Assessment

Begin by assessing the distribution and severity of terminal hair growth using the modified Ferriman-Gallwey (mFG) score, evaluating nine body sites (upper lip, chin, chest, upper and lower back, upper and lower abdomen, upper arms and thighs), with hirsutism defined as mFG >4-6 depending on ethnicity. 1, 2

Key History Elements to Obtain

• Menstrual history: Oligomenorrhea or amenorrhea suggests PCOS or other ovulatory dysfunction 1, 3
• Onset and progression: Rapid onset over weeks to months raises concern for androgen-secreting tumors 1
• Associated symptoms: Acne, androgenetic alopecia, clitoromegaly, truncal obesity, or infertility 1, 3
• Signs of insulin resistance: Obesity, acanthosis nigricans 1
• Medication history: Exogenous androgens, certain antiepileptic drugs 1
• Family history: Similar conditions in relatives (strong genetic component) 1, 4

Physical Examination Findings

• Pelvic examination: Assess for adnexal masses suggesting ovarian tumors 1
• Signs of virilization: Clitoromegaly, deepening voice, increased muscle mass 1, 5
• Metabolic features: Acanthosis nigricans, central obesity 1
• Scalp examination: Androgenetic alopecia pattern 1, 3

Laboratory Testing Algorithm

Mild Hirsutism Without Other Hyperandrogenic Signs

Routine endocrinologic testing is NOT indicated for mild hirsutism without oligomenorrhea, infertility, clitoromegaly, truncal obesity, or rapid onset. 1

Moderate-to-Severe Hirsutism or Associated Symptoms

Full endocrine evaluation is mandatory when hirsutism occurs with oligomenorrhea, amenorrhea, infertility, clitoromegaly, truncal obesity, or rapid onset. 1

First-Line Laboratory Tests

• Total testosterone or free/bioavailable testosterone: Use LC-MS/MS method if available (gold standard with superior accuracy over immunoassay) 1, 3

  • Levels >200 ng/dL highly suggest androgen-secreting tumor (ovarian or adrenal) 1, 5
  • Elevated testosterone with normal FSH/LH strongly suggests ovarian androgen excess 3

• DHEA-S (dehydroepiandrosterone sulfate): Normal DHEA-S effectively rules out adrenal causes including non-classical congenital adrenal hyperplasia and adrenal tumors 1, 3

• 17-hydroxyprogesterone: Consider based on clinical suspicion for non-classical congenital adrenal hyperplasia (21-hydroxylase deficiency) 1

• TSH (thyroid-stimulating hormone): Screen for thyroid dysfunction 1, 6

• Prolactin: Exclude hyperprolactinemia, which can cause menstrual irregularity and hirsutism 1, 3

• Fasting glucose and insulin: Assess for insulin resistance, particularly in obese patients 1, 3

• Lipid panel: Evaluate metabolic syndrome risk 3

Additional Testing Based on Initial Results

• Free androgen index or free testosterone: Calculate to assess bioavailable androgen, as SHBG fluctuations affect interpretation 3

• FSH and LH: Normal gonadotropins exclude primary ovarian failure and suggest functional ovarian hyperandrogenism rather than hypothalamic-pituitary dysfunction 3

• Androstenedione: May provide additional information about androgen excess 1

Imaging Studies

Pelvic Ultrasound

Perform pelvic ultrasound to detect polycystic ovaries (>10 peripheral cysts, 2-8 mm diameter, with thickened ovarian stroma) in women with suspected PCOS. 1

When to Consider Additional Imaging

• Adrenal or ovarian imaging (CT/MRI): If testosterone >200 ng/dL or DHEA-S markedly elevated, to evaluate for androgen-secreting tumors 1, 5

Common Diagnostic Pitfalls

• Do not perform microbiologic testing: This is not indicated for hirsutism evaluation 1

• Recognize ethnic variation: Diagnostic mFG cut-offs vary by ethnicity; Asian women may have lower scores despite androgen excess 2, 4

• Do not dismiss patient concerns: Women who complain of excess unwanted hair should be evaluated regardless of observable severity on examination, as hirsutism has significant psychosocial impact 2

• Remember PCOS diagnostic criteria: PCOS requires only 2 of 3 criteria (hyperandrogenism, ovulatory dysfunction, or polycystic ovaries) and accounts for 70-80% of hirsutism cases 1, 4

Differential Diagnosis Framework

Most Common Causes (>95% of cases)

• Polycystic ovary syndrome (PCOS): 70-80% of hirsutism cases 1, 4
• Idiopathic hirsutism: 5-15% of cases, with normal ovulatory function and androgen levels 2, 4
• Non-classical congenital adrenal hyperplasia: 1-10% depending on ethnicity 2

Rare but Important Causes

• Androgen-secreting tumors: Ovarian or adrenal 1, 2
• Cushing's syndrome 1, 2
• Medication-induced: Exogenous androgens, certain antiepileptics 1
• Ovarian hyperthecosis 2
• Acromegaly 2

Special Population Considerations

• Women with epilepsy: Higher PCOS prevalence (10-25%) even without antiepileptic drugs; certain antiepileptics may trigger or worsen hirsutism 1

• Adolescents: May benefit from early intervention, particularly those with endocrine comorbidities 1

• Patients with history of uterine polyps: Ensure adequate surveillance given unopposed estrogen exposure from chronic anovulation 1