How should I evaluate a pediatric patient (child or adolescent) presenting with excess terminal hair growth (hirsutism)?

Workup of Hirsutism in Pediatric Patients

In a pediatric patient presenting with hirsutism, first confirm true terminal hair growth in androgen-dependent areas, then immediately assess for signs of virilization or rapid progression that would indicate an androgen-secreting tumor requiring urgent imaging, followed by targeted hormonal evaluation based on pubertal status and associated clinical features.

Initial Clinical Assessment

Confirm True Hirsutism vs. Hypertrichosis

• Hirsutism refers specifically to excessive terminal (coarse) hair growth in androgen-dependent areas (upper lip, chin, chest, abdomen, back, inner thighs) in a male-like pattern 1, 2
• Distinguish from hypertrichosis, which is generalized excessive hair growth not limited to androgen-dependent areas 3
• Use the modified Ferriman-Gallwey (mFG) scoring system: scores ≥4-6 indicate hirsutism, though ethnic variation exists 3, 2

Red-Flag Features Requiring Urgent Evaluation

Immediately assess for virilization or tumor indicators:

• Virilization signs: clitoromegaly, deepening voice, increased muscle mass, male-pattern baldness, breast atrophy 4, 5
• Rapid onset (weeks to months) or severe progression suggests androgen-secreting tumor 5, 3
• Very elevated testosterone (total testosterone >200 ng/dL) strongly suggests tumor 5
• If any of these are present, proceed directly to pelvic ultrasound and adrenal imaging before extensive hormonal workup 5

Pubertal Status and Age-Specific Considerations

Prepubertal children (Tanner stage 1):

• Hirsutism with early body odor, axillary/pubic hair, accelerated growth, advanced bone age, or genital maturation indicates premature adrenarche or virilizing disorder 4
• Obtain growth charts and hand radiograph for bone age as initial screening tools 4
• Consider Cushing syndrome if accompanied by weight gain with growth deceleration, buffalo hump, moon facies, or wide violaceous striae 4, 5

Postpubertal adolescents:

• Assess for menstrual irregularities: oligomenorrhea (<9 cycles/year), amenorrhea (>6 months without menses), or polymenorrhea 5, 6
• Look for PCOS features: acne, androgenic alopecia, acanthosis nigricans (insulin resistance marker), truncal obesity (waist-hip ratio >0.9) 4, 5, 6
• Evaluate for infertility concerns if sexually active 5

Laboratory Evaluation Algorithm

First-Tier Testing (All Patients with Confirmed Hirsutism)

Morning (08:00-09:00h) fasting blood draw:

• Total testosterone (or free/bioavailable testosterone if total is normal but clinical suspicion high) 4, 5, 3
• DHEA-S (dehydroepiandrosterone sulfate) to assess adrenal androgen production 4, 5
• 17-hydroxyprogesterone (early morning, follicular phase if menstruating) to screen for non-classic congenital adrenal hyperplasia 4, 5, 6
• Prolactin (hyperprolactinemia occurs in 65% of pediatric GH excess cases and can cause hirsutism) 4, 7
• TSH (thyroid dysfunction is part of PCOS differential) 4, 5

Interpretation and Second-Tier Testing

If total testosterone >200 ng/dL:

• Urgent pelvic ultrasound to evaluate for ovarian tumor 5
• Adrenal CT or MRI to evaluate for adrenal tumor 5

If 17-hydroxyprogesterone elevated:

• Perform ACTH stimulation test to confirm non-classic congenital adrenal hyperplasia (21-hydroxylase deficiency) 4, 5, 6

If oligomenorrhea/amenorrhea present with moderate hirsutism:

• LH and FSH (LH:FSH ratio >2:1 suggests PCOS) 4, 5
• Fasting glucose and insulin or oral glucose tolerance test to assess insulin resistance 5, 6
• Lipid panel to screen for metabolic syndrome 6
• Pelvic ultrasound to identify polycystic ovarian morphology (>10 peripheral cysts 2-8mm diameter with thickened stroma) 5

If Cushing syndrome suspected (weight gain with growth deceleration, striae, moon facies):

• 24-hour urinary free cortisol (3 consecutive collections; >193 nmol/24h or >70 μg/m² abnormal) 4
• Late-night salivary cortisol (95% sensitivity, 100% specificity) 4
• Low-dose dexamethasone suppression test (0.5mg every 6 hours for 48h; failure to suppress cortisol <50 nmol/L indicates Cushing syndrome) 4
• If hypercortisolism confirmed, measure 09:00h plasma ACTH to distinguish ACTH-dependent from ACTH-independent causes 4

If GH excess suspected (excessive height >2 SDS, accelerated growth velocity, acromegalic features):

• IGF-1 (age-, sex-, and Tanner stage-adjusted; elevated in 100% of GH excess) 4, 7
• Oral glucose tolerance test with GH measurements (failure to suppress GH <1 μg/L suggests GH excess, though 30% of tall children fail to suppress normally) 4, 7
• Pituitary MRI with contrast if biochemical testing positive 4, 7

Diagnostic Criteria for Common Causes

Polycystic Ovary Syndrome (PCOS)

Accounts for 70-80% of hirsutism cases 5, 1

In adolescents, diagnosis requires both of the following 4, 5:

• Hyperandrogenism (clinical hirsutism/acne OR biochemical elevation of androgens)
• Persistent oligomenorrhea (irregular cycles >2 years post-menarche)

In adults, diagnosis requires any 2 of 3 Rotterdam criteria 4, 5:

• Hyperandrogenism (clinical or biochemical)
• Ovulatory dysfunction (oligo- or anovulation)
• Polycystic ovaries on ultrasound

Idiopathic Hirsutism

• Accounts for 5-15% of hirsutism cases 1, 2
• Normal ovulatory cycles (regular menses every 21-35 days) 1
• Normal androgen levels (testosterone, DHEA-S, 17-hydroxyprogesterone all within reference range) 1, 2
• Diagnosis of exclusion after ruling out other causes 2

Non-Classic Congenital Adrenal Hyperplasia

• Accounts for 1-10% of hirsutism (varies by ethnicity) 2
• Elevated basal 17-hydroxyprogesterone (typically >200 ng/dL) 5, 6
• Confirmed by exaggerated 17-hydroxyprogesterone response to ACTH stimulation (>1000 ng/dL at 60 minutes) 4

When to Omit Extensive Hormonal Testing

Routine endocrinologic evaluation is NOT recommended for 4:

• Mild hirsutism (mFG score <8) without other signs of hyperandrogenism
• Isolated acne without hirsutism, menstrual irregularity, or virilization
• Patients with clear exogenous androgen exposure (anabolic steroids, certain antiepileptics)

Critical Pitfalls to Avoid

• Do not dismiss prepubertal hirsutism as "early puberty" without evaluating for premature adrenarche, virilizing tumors, or Cushing syndrome 4
• Do not delay imaging in patients with rapid-onset hirsutism, virilization, or very elevated testosterone (>200 ng/dL), as these indicate possible malignancy 5, 3
• Do not diagnose PCOS in early adolescence (<2 years post-menarche) based solely on irregular cycles, as menstrual irregularity is physiologic during this period 4, 5
• Do not overlook Cushing syndrome in children with hirsutism plus unexplained weight gain and growth deceleration—this combination has high sensitivity and specificity 4
• Do not use overnight dexamethasone suppression test alone in pediatrics (only 11-75% sensitivity); use 24-hour urinary free cortisol or late-night salivary cortisol instead 4
• Do not forget genetic evaluation in prepubertal patients or those with family history of pituitary adenomas, as nearly 50% of pediatric pituitary tumors have identifiable genetic causes 4, 7