How should a 15-year-old girl presenting with hair loss be evaluated and managed?

Evaluation and Management of Hair Loss in a 15-Year-Old Girl

A 15-year-old girl with hair loss should first undergo focused scalp examination to distinguish between patchy loss (suggesting alopecia areata) versus diffuse thinning (suggesting telogen effluvium or androgenetic alopecia), with dermoscopy to identify exclamation mark hairs pathognomonic for alopecia areata, followed by targeted laboratory testing only if the diagnosis is uncertain or signs of systemic disease are present. 1, 2

Initial Clinical Assessment

Scalp Examination Findings

• Examine the pattern of hair loss carefully: Discrete patches with exclamation mark hairs (short broken hairs at margins) confirm alopecia areata, while diffuse thinning over the central scalp with preserved frontal hairline indicates androgenetic alopecia 1, 2
• Use dermoscopy when available: Yellow dots and exclamation mark hairs are pathognomonic for alopecia areata and make the diagnosis without biopsy 1, 2
• Check for scalp inflammation or scaling: These findings suggest tinea capitis or early scarring alopecia rather than alopecia areata or androgenetic alopecia 1
• Assess Tanner stage and look for signs of androgen excess (acne, hirsutism) that might indicate polycystic ovary syndrome 3, 4

Critical History Elements

• Duration of hair loss: Onset less than 1 year suggests better prognosis, with 34-50% of alopecia areata patients recovering spontaneously within one year 3, 1
• Recent triggers: Ask about physiologic stress (illness, surgery, rapid weight loss), emotional stress, or medications that could cause telogen effluvium 2, 5
• Family history: Present in 20% of alopecia areata cases and helps confirm diagnosis 3, 2
• Hair care practices: Tight hairstyles suggest traction alopecia; compulsive pulling behaviors suggest trichotillomania 3, 6

Laboratory Testing Strategy

Most cases of alopecia areata require no laboratory testing when the diagnosis is clinically evident with characteristic dermoscopic findings. 3, 1 However, targeted testing is appropriate when:

When to Order Labs

• The diagnosis is uncertain or presentation is atypical 3, 1
• Diffuse hair loss without clear patches 1, 2
• Signs of systemic disease are present 3, 1

Recommended Tests (When Indicated)

• Fungal culture: Only if scalp inflammation or scaling suggests tinea capitis 3, 1
• Serum ferritin: Check if iron deficiency suspected; optimal level ≥60 ng/mL needed for hair growth 1
• TSH and free T4: Thyroid disease commonly causes hair loss in adolescents 1, 4
• Vitamin D level: 70% of alopecia areata patients are deficient (<20 ng/mL) versus 25% of controls, with lower levels correlating with disease severity 2
• Total testosterone, free testosterone, and SHBG: Only if signs of androgen excess present (acne, hirsutism, irregular periods) 1, 4

Tests to Avoid

• Do not order extensive autoimmune panels in straightforward alopecia areata cases, as the modest increase in autoimmune disease prevalence does not justify routine screening 3, 1

Management Algorithm

For Limited Patchy Alopecia Areata (≤5 patches, each ≤3 cm)

Watchful waiting with reassurance is the recommended first approach, as 34-50% recover within one year without treatment. 3, 1 Counsel that:

• Visible regrowth is unlikely within the first 3 months after a new patch appears 1
• No treatment alters the long-term natural history of the disease 3, 1

If treatment is desired:

• Intralesional triamcinolone acetonide 5-10 mg/mL injected 0.05-0.1 mL just beneath the dermis produces regrowth in 62% of patients with monthly injections (Strength of recommendation B, Quality III) 1
• The main drawback is patient discomfort during injections 1

For Extensive Alopecia Areata (>50% scalp involvement)

• Contact immunotherapy with diphenylcyclopropenone (DPCP) is the best-documented treatment but achieves response in less than 50% of appropriately selected candidates and requires multiple hospital visits over months (Strength of recommendation B, Quality II-ii) 1
• Wigs provide immediate cosmetic benefit and are often the most practical solution for extensive, longstanding disease 1

For Androgenetic Alopecia (If Diagnosed)

• Topical minoxidil 2% solution twice daily is first-line treatment for adolescent girls, though systematic evaluation in this age group is limited 7, 8
• Treatment must be continuous to maintain results; stopping will result in resumption of hair loss 1
• Allow minoxidil to stay on scalp for about 4 hours before washing for best results 7
• Results may not be visible for 2-4 months 7

For Telogen Effluvium

• Identify and remove the precipitating trigger (stress, nutritional deficiency, illness) 5, 6
• Spontaneous remission occurs in up to 80% of cases with short duration (<1 year) once the trigger is removed 9, 5
• Supplement nutritional deficiencies if identified (vitamin D, zinc, iron) 2, 9

For Tinea Capitis

• Requires systemic oral antifungal therapy; topical treatment is insufficient 2
• Fungal culture is mandatory before treatment 2

Common Pitfalls to Avoid

• Do not mistake trichotillomania for alopecia areata: In trichotillomania, broken hairs remain firmly anchored in anagen phase, whereas alopecia areata shows exclamation mark hairs 3, 1
• Do not overlook the psychological impact: Hair loss can profoundly affect self-esteem in adolescents; patients who become withdrawn or experience social difficulties should be considered for mental health referral 1, 4, 6
• Do not force examination: If the patient is not tolerating the examination, stop and try again later to minimize negative experiences 3
• Do not use potent topical corticosteroids for alopecia areata due to lack of convincing evidence 1
• Do not use systemic corticosteroids or PUVA due to potentially serious side effects and inadequate efficacy evidence 3

When to Refer to Dermatology

• Uncertain diagnosis despite clinical examination and dermoscopy 10, 6
• Extensive alopecia areata requiring contact immunotherapy 1
• Suspected scarring alopecia (best evaluated by dermatologist) 5
• Treatment-resistant cases 10
• Need for scalp biopsy when diagnosis remains unclear 3, 1