How do you assess hair loss?

Comprehensive Approach to Hair Loss Assessment

Definition

Hair loss (alopecia) encompasses both scarring and nonscarring patterns, with nonscarring types being most common and potentially reversible with appropriate treatment. 1, 2

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Classification Systems

Primary Categories

• Nonscarring alopecia: Includes androgenetic alopecia, alopecia areata, telogen effluvium, anagen effluvium, trichotillomania, and tinea capitis 1, 2
• Scarring alopecia: Permanent follicle destruction (e.g., lupus erythematosus) 1
• Hair shaft abnormalities: Fragility disorders causing breakage patterns 3

Pattern-Specific Classification

• Males: Hamilton-Norwood classification system (temples, vertex, mid-frontal scalp involvement) 4, 5
• Females: Ludwig system (central thinning with preserved frontal hairline) 4, 5
• Alopecia areata severity: Based on extent (<25% vs >50% scalp involvement), location (ophiasis pattern), duration, and quality of life impact 6, 7

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Differential Diagnosis

Autoimmune

• Alopecia areata: T-lymphocyte-mediated attack on follicles; patchy, well-demarcated nonscarring loss; 20% family history; associated with thyroid disease, lupus, vitiligo 1

Nutritional/Metabolic

• Iron deficiency: Most common nutritional cause worldwide; chronic diffuse telogen loss 1
• Vitamin D deficiency: 70% prevalence in alopecia areata vs 25% controls; inverse correlation with severity 1
• Zinc deficiency: Lower levels in alopecia areata, especially resistant cases >6 months 1
• Thyroid disease: Both hypo- and hyperthyroidism cause diffuse thinning 1

Hormonal

• Androgenetic alopecia: DHT sensitivity causing miniaturization; patterned distribution 4, 1
• Polycystic ovary syndrome: Associated with androgen excess, acne, hirsutism, irregular periods 1

Stress/Physiologic

• Telogen effluvium: Stressors (illness, surgery, childbirth, rapid weight loss, emotional trauma) push follicles into telogen phase prematurely 1

Medication-Induced

• Anagen effluvium: Chemotherapy interrupts actively growing follicles; rapid, severe onset 1

Infectious

• Tinea capitis: Fungal infection with inflammation, scaling, patchy loss; requires oral antifungals 1

Physical/Behavioral

• Trichotillomania: Compulsive pulling; incomplete loss with firmly anchored broken hairs in anagen phase 1, 7

Systemic Disease

• Systemic lupus erythematosus: Scarring or nonscarring patterns 1
• Secondary syphilis: "Moth-eaten" patchy loss 1

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History Taking

Character of Hair Loss

• Onset: Acute vs gradual; sudden suggests telogen effluvium or alopecia areata 3, 8
• Pattern: Diffuse vs patchy vs patterned distribution 3, 8
• Progression: Stable, expanding, or fluctuating 3, 8
• Shedding: Increased hair on pillow, shower drain, or brush 3, 8
• Texture changes: Miniaturization, thinning, or brittleness 3, 8

Red Flags

• Scarring: Permanent follicle destruction requiring urgent evaluation 1, 3
• Scalp inflammation: Erythema, scaling, pustules suggest infection or inflammatory scarring alopecia 1, 3
• Systemic symptoms: Fever, weight loss, fatigue, joint pain suggest lupus or other systemic disease 1, 3
• Rapid progression: Especially with constitutional symptoms 3, 8
• Childhood onset with >50% loss: Poor prognosis in alopecia areata 1, 7
• Ophiasis pattern: Scalp margin involvement predicts worse outcomes 1

Risk Factors

• Family history: 20% in alopecia areata; strong predictor for androgenetic alopecia 1
• Autoimmune diseases: Thyroid disease, vitiligo, lupus, diabetes 1
• Recent stressors: Surgery, childbirth, severe illness, emotional trauma, rapid weight loss within 3 months 1
• Medications: Chemotherapy, anticoagulants, beta-blockers, retinoids, antithyroid drugs 1
• Nutritional deficiencies: Restrictive diets, malabsorption, bariatric surgery 1
• Hair practices: Tight hairstyles, chemical treatments, heat styling 3, 8
• Hormonal factors: Pregnancy, menopause, oral contraceptive changes 1

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Physical Examination (Focused)

Scalp Inspection

• Distribution: Diffuse, patchy, or patterned (frontal, vertex, temporal) 3, 8
• Scarring vs nonscarring: Absence of follicular ostia indicates scarring 3, 8
• Inflammation: Erythema, scaling, pustules, crusting 3, 8
• Exclamation mark hairs: Short broken hairs (2-3mm) with tapered proximal ends at patch margins in alopecia areata 1, 7

Pull Test

• Technique: Grasp 40-60 hairs between thumb and forefinger; gentle traction 3, 8
• Positive result: >6 hairs extracted suggests active shedding (telogen effluvium, alopecia areata) 3, 8
• Negative result: <6 hairs suggests stable or chronic process 3, 8

Trichoscopy (Dermoscopy of Scalp)

• Yellow dots: Most common in alopecia areata (6-100%); regularly round indicates active disease 7
• Black dots: Fractured hairs at scalp surface; present in 0-84% of alopecia areata 7
• Exclamation mark hairs: Diagnostic for alopecia areata vs trichotillomania 7
• Cadaverized hairs: Dystrophic hairs in alopecia areata 1
• Perifollicular scaling: Suggests seborrheic dermatitis or psoriasis 7

Hair Shaft Examination

• Miniaturization: Thin, short vellus hairs in androgenetic alopecia 4
• Broken hairs: Firmly anchored in trichotillomania vs easily extracted in alopecia areata 1, 7
• Anagen:telogen ratio: Normally 90:10; reversed in telogen effluvium 4

Systemic Examination

• Signs of androgen excess: Acne, hirsutism, male-pattern fat distribution 1
• Thyroid examination: Goiter, thyroid nodules, signs of hypo/hyperthyroidism 1
• Skin examination: Vitiligo, lupus rash, nail pitting (alopecia areata association) 1

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Investigations and Expected Findings

First-Line Laboratory Tests

• Serum ferritin: <40 ng/mL suggests iron deficiency; lower in women with alopecia areata and androgenetic alopecia 1
• Vitamin D (25-OH): <20 ng/mL (<50 nmol/L) is deficient; 70% prevalence in alopecia areata vs 25% controls; inverse correlation with severity 1
• Serum zinc: Lower in alopecia areata, especially resistant disease >6 months 1
• TSH: Elevated with low free T4 indicates hypothyroidism; suppressed with elevated free T4 indicates hyperthyroidism 1
• Thyroid peroxidase (TPO) antibodies: If biochemical hypothyroidism confirmed 1

Second-Line Tests (When Indicated)

• Total/free testosterone and SHBG: In women with signs of androgen excess (acne, hirsutism, irregular periods) 1
• Prolactin: If hyperprolactinemia suspected 1
• 2-hour oral glucose tolerance test: If diabetes or insulin resistance suspected 1
• Fasting lipid panel: Evaluate dyslipidemia associated with PCOS 1
• Folate level: May contribute to hair loss when deficient 1

Microbiologic Testing

• Fungal culture (KOH prep): When tinea capitis suspected; requires oral antifungal therapy 1, 7

Serologic Testing

• Lupus serology (ANA, anti-dsDNA): When systemic lupus in differential 1
• Syphilis serology (RPR/VDRL): When secondary syphilis suspected 1

Invasive Testing

• Scalp biopsy (4mm punch): Indicated for uncertain diagnosis, atypical presentation, suspected early scarring alopecia, or diffuse alopecia areata challenging to diagnose clinically 1, 7
• Biopsy site selection: Use trichoscopy to identify optimal location with active disease 7
• Expected findings in alopecia areata: Peribulbar lymphocytic infiltrate ("swarm of bees"), increased telogen/catagen follicles, preserved follicular architecture 1

Photographic Documentation

• Standardized photography: Before-and-after comparison for treatment response 4
• Trichoscopy images: Objective evaluation at follow-up visits 7
• Hair counts: Number of hairs per cm² before and after treatment 4
• Hair diameter measurement: Micrometer assessment; increased diameter indicates positive response 4

Clinical Scoring Systems

• Global Physician Assessment (GPA): Standardized severity grading 4
• Patient Self-Assessment Questionnaire: Satisfaction and perceived improvement 4
• Trichogram: Computer analysis of hair density, diameter, terminal/vellus ratio 4

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Empiric Treatment

Alopecia Areata

• Intralesional corticosteroids: First-line for limited patchy disease (<50% scalp); triamcinolone acetonide 5-10 mg/mL every 4-6 weeks (Strength of recommendation B, Quality of evidence III) 1
• Contact immunotherapy: Best-documented for extensive patchy disease; lower response in severe cases 1
• Vitamin D supplementation: For levels <20 ng/mL, though no double-blind trials yet confirm efficacy 1
• Zinc supplementation: When deficient, particularly in resistant cases 1

Androgenetic Alopecia

• FDA-approved medications: Minoxidil (topical) and finasteride (oral for males) 4
• PRP therapy: Increases hair density, follicle diameter, terminal hair density; combined with minoxidil most effective 4
• PRP protocol: Higher platelet concentration more effective; microneedling superior to injection for application 4

Telogen Effluvium

• Address underlying trigger: Correct nutritional deficiencies, manage stress, discontinue offending medications 1
• Iron supplementation: If ferritin <40 ng/mL 1
• Reassurance: 34-50% of alopecia areata cases recover within one year without treatment 1

Tinea Capitis

• Oral antifungal therapy: Required (topical agents insufficient); griseofulvin or terbinafine 1

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Indications to Refer

Dermatology Referral

• Scarring alopecia: Urgent referral for permanent follicle destruction 1, 3
• Uncertain diagnosis: After initial evaluation and trichoscopy 1, 7
• Extensive alopecia areata: >50% scalp involvement; poor prognosis requiring specialist management 1, 7
• Ophiasis pattern: Scalp margin involvement predicts worse outcomes 1
• Childhood-onset alopecia areata: Poorer prognosis requiring aggressive treatment 1
• Failed empiric treatment: No response after 6 months 1
• Biopsy needed: For definitive diagnosis in complex cases 1, 7

Endocrinology Referral

• Confirmed PCOS: Requires comprehensive hormonal management 1
• Thyroid disease: If complex or refractory to primary care management 1
• Hyperprolactinemia: Requires pituitary evaluation 1

Psychiatry/Psychology Referral

• Trichotillomania: Compulsive behavior requiring cognitive-behavioral therapy 1
• Significant psychological distress: Anxiety, depression, social disability from hair loss 1
• Quality of life impact: Severe distress warranting mental health assessment 4, 1

Infectious Disease Referral

• Secondary syphilis: Requires systemic treatment and partner notification 1
• Refractory tinea capitis: Failed standard oral antifungal therapy 1

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Critical Pitfalls to Avoid

Diagnostic Errors

• Ordering excessive laboratory tests when diagnosis is clinically evident: Alopecia areata is typically diagnosed clinically without workup 1
• Failing to perform trichoscopy: Simple, non-invasive bedside tool that aids diagnosis, guides biopsy site selection, and monitors treatment response 7
• Missing scarring alopecia: Permanent follicle destruction requires urgent intervention; look for absent follicular ostia 1, 3
• Overlooking systemic disease: Lupus, syphilis, thyroid disease can present as hair loss 1
• Confusing trichotillomania with alopecia areata: Broken hairs remain firmly anchored in trichotillomania vs exclamation mark hairs in alopecia areata 1, 7
• Missing tinea capitis: Subtle signs; requires fungal culture for diagnosis 1

Management Errors

• Ignoring psychological impact: Hair loss causes significant distress; assess for anxiety and depression 1
• Failing to address nutritional deficiencies: Iron, vitamin D, zinc deficiencies are common and treatable 1
• Overtreatment of self-limited disease: 34-50% of alopecia areata recovers within one year without treatment 1
• Using topical antifungals for tinea capitis: Oral therapy required for scalp infections 1
• Inadequate PRP protocol: Low platelet concentration, low volume, or inadequate frequency reduces effectiveness 4

Prognostic Errors

• Underestimating poor prognostic factors: <25% initial hair loss has 68% disease-free rate vs only 8% for >50% loss 7
• Missing ophiasis pattern: Scalp margin involvement predicts worse outcomes 1
• Overlooking childhood onset: Poorer prognosis requiring early aggressive intervention 1

Follow-Up Errors

• Inadequate photographic documentation: Standardized images essential for objective treatment response assessment 4, 7
• Premature discontinuation of treatment: Many therapies require 6-12 months for visible improvement 1
• Failing to monitor for treatment complications: Intralesional steroids can cause atrophy; contact immunotherapy has sensitization risks 1