Types

• Acute

  • Occurs at any age, including kids, more common in women than men

• Chronic

  • Less common, most frequently in women between 30 and 60

Pathogenesis

Normal hair cycle has three phases: anagen (growth), catagen (transformation) and telogen (rest). Every hair is in a different cycle so instead of mass shedding of hair, 50 to 150 hairs shed each day on average.

In Telogen Effluvium (TE), the amount of hairs in telogen phase increases resulting in prominent hair shedding. Normally <10% of hair as in telogen, in TE between 7 and 35% of hairs shift to telogen phase.

The mechanism is not well understood.

The theory is an identifiable or occult event stimulates a change in the cycle.

• Immediate anagen release. Many anagen follicles are stimulated to enter telogen phase prematurely e.g. high fever, drugs

• Delayed anagen release. Prolongation of the duration of anagen, therefore delaying telogen. Delay anagen release may be the primary mechanism for post-partum telogen effluvium.

Inciting Factors

Acute or chronic major illness (eg, systemic rheumatic disease [collagen vascular disease], febrile illness, major surgery)

• Childbirth (telogen gravidarum)

• Significant emotional stress

• Nutritional changes:

  • Rapid weight loss

  • Protein or caloric dietary restriction

  • Nutritional deficiencies (eg, iron deficiency anemia, congenital or acquired zinc deficiency)

• Endocrine disorders (eg, hypothyroidism, hyperthyroidism, androgen excess)

• Drugs, supplements, or toxins (eg, heavy metals)

• Inflammatory conditions of the scalp (eg, seborrheic dermatitis, psoriasis)

• Infectious conditions that affect the scalp (eg, fungal, bacterial, viral, or spirochetal)

• Low vitamin D and serum ferritin have been proposed but evidence lacking

Clinical Features

• Acute or chronic reduction in scalp hair density of <50%

• Typically diffuse but can be more noticable in the bitemporal pattern

• In the absence of a concurrent hair or scalp disorder, the scalp and hair shafts appear normal.

• TE may lead to recognition of a pre-existing hair loss disorder that was not obviously previously

Diagnosis

Can be made on history, exam and hair pull test

• Key questions include course of hair loss (date of onset, duration, triggers)

• Characteristics

• Medical history

  • Recent illness

  • Surgery

  • Weight loss

  • Restrictive diets

  • Childbirth, miscarriage or abortion

  • Iron deficiency anaemia

  • Nutritional deficiency

  • Thyroid disorder

• Psychosocial stressors

• Drugs

• Toxic exposure

• Family history of hair disease

Exam

• Scalp looking for extend of hair loss, scale

• Shafts look normal

• Nails

• Hair pull test

• Dermoscopy

Tests

• FBC

• UEC LFT

• TSH

• Ferritin

• Vit D

• Other tests depend on history

Differential Diagnosis

• Anagen effluvium due to chemo / toxins

• Androgenetic alopecia

• Diffuse alopecia areata

• Loose anagen syndrome

Management

• Remove or treat any known underlying cause

  • ASsociated illness

  • Dietary deficiency

  • Drugs

  • Concomitant hair disorders

• Psychological support

• Education

  • If the cause of hair loss is eliminated or treated, hair loss resolves and regrows in 6 to 12 months

• Follow up

• Cosmetic measures

• Limited evidence for iron in the absence of deficiency

• Supplements such as zinc, biotin, Vit D in the absence of deficiency is unclear

• Topical minoxidil is controversial

Prognosis

• Active shedding for 2 to 3 months

• Followed by stabilisation

• Cosmetically significant improvement is noted within 6 to 12 months

• TE in which the underlying cause cannot be identified or removed may persist for ye

References

• Telogen Effluvium - UpToDate