What are the key differences in diagnosis and treatment between acute and chronic telogen effluvium (excessive hair shedding) in patients?

Acute vs Chronic Telogen Effluvium: Key Differences

The primary distinction between acute and chronic telogen effluvium lies in duration: acute TE resolves spontaneously within 6 months once the trigger is eliminated, while chronic TE persists beyond 6 months and can fluctuate for years, requiring more aggressive management including consideration of oral minoxidil. 1, 2, 3

Diagnostic Differences

Acute Telogen Effluvium

• Onset occurs 3-4 months after a specific triggering event (physiological stress, drugs, trauma, nutritional deficiency, illness) 1, 4
• Duration is self-limited, typically resolving within 6 months once the causative factor is removed 1, 5
• Spontaneous remission occurs in up to 80% of cases with short duration (<1 year) 6, 7
• Patients present with sudden, often severe shedding that may come out in handfuls initially 3

Chronic Telogen Effluvium

• Defined by persistent diffuse hair shedding lasting more than 6 months, often for years 2, 3
• Typically affects women aged 30-60 years who had full hair prior to onset 3
• Characterized by fluctuating severity over years rather than steady progression 3
• No obvious triggering cause can be identified in many cases 3
• May be primary or secondary to ongoing causes including drug reactions, nutritional deficiencies, or female pattern hair loss 2

Clinical Evaluation Approach

Essential First-Line Laboratory Testing

For both acute and chronic presentations, obtain: 8, 6, 7

• Serum ferritin (supplement if <60 ng/mL) 8, 7
• TSH (complete with free T4 and anti-TPO antibodies if abnormal) 8, 6, 7
• Vitamin D level (supplement if <20 ng/mL) 8, 6
• Serum zinc level 8, 6, 7
• Complete blood count 8, 7

Additional Testing When Indicated

• If signs of androgen excess present (hirsutism, severe acne, irregular periods): obtain total or free testosterone, SHBG, screen for PCOS, and prolactin if hyperprolactinemia suspected 8, 7
• If diagnosis uncertain: consider scalp biopsy to exclude diffuse alopecia areata, early scarring alopecia, or female pattern hair loss 8, 6, 7
• If tinea capitis suspected: fungal culture 8, 6

Diagnostic Tests for Hair Loss Assessment

• Hair wash test: quantifies shedding and monitors treatment response 1, 5
• Trichogram or phototrichogram: assesses telogen percentage and hair density 1, 5
• Scalp biopsy: confirms diagnosis when clinical picture is unclear, particularly to exclude miniaturization suggesting androgenetic alopecia 1, 2

Treatment Differences

Acute Telogen Effluvium Management

The cornerstone is identifying and eliminating the triggering factor 6, 1, 4

• Watchful waiting is appropriate given the 80% spontaneous remission rate in cases <1 year duration 6, 7
• Address nutritional deficiencies identified on laboratory testing: 8, 6
  • Iron supplementation for ferritin <60 ng/mL with reassessment at 3 months 8
  • Vitamin D supplementation for levels <20 ng/mL 8, 6
  • Zinc supplementation when deficient 8, 6
• Topical 5% minoxidil may accelerate recovery and provide psychological reassurance, though this is off-label use 5
  • In a clinical trial, topical minoxidil increased terminal hair count by 12.55 hairs/cm² at week 4 and showed improvement in nearly 70% of subjects by week 24 5
  • Apply 1 mL twice daily to entire scalp 5

Chronic Telogen Effluvium Management

More aggressive intervention is warranted given the persistent nature and psychological burden 2, 3

• Oral minoxidil is the most effective treatment for chronic TE, showing significant reduction in hair shedding 2
  • Dosing ranges from 0.25-2.5 mg once daily 2
  • Mean hair shedding score reduction of 1.7 at 6 months and 2.58 at 12 months (p<0.001) 2
  • Monitor blood pressure (mean change was minimal: -0.5 mmHg systolic, +2.1 mmHg diastolic) 2
  • Common side effect is facial hypertrichosis (occurred in 13/36 women), which may require waxing or laser hair removal 2
  • Transient postural dizziness and ankle edema are less common 2
• Continue nutritional supplementation as indicated by laboratory results 8, 6
• Repeated reassurance is essential: patients fear total baldness, but chronic TE represents shedding rather than permanent hair loss and does not cause complete baldness 3
• Chronic TE is self-limiting in the long run, though it may fluctuate for years 3

Critical Pitfalls to Avoid

• Failing to distinguish chronic TE from female pattern hair loss: scalp biopsy showing no miniaturization confirms chronic TE diagnosis 2
• Overlooking the psychological impact: chronic TE causes severe psychological stress requiring empathetic counseling and reassurance 2, 3
• Inadequate follow-up: ferritin should be rechecked at 3 months after iron supplementation 8
• Missing the self-limited nature of acute TE: avoid overtreatment when watchful waiting is appropriate 6, 7, 5
• Confusing chronic TE with alopecia areata: dermoscopy showing yellow dots and exclamation mark hairs indicates alopecia areata, not TE 8
• Not addressing trichodynia: patients with scalp pain may experience improvement or resolution within 3 months of oral minoxidil treatment 2