II. Causes: Focal

  1. Diffuse
    1. Androgenetic Alopecia
      1. Male-Patterned Hair Loss (M-patterned hair thinning)
      2. Female-Patterned Hair Loss (central hair thinning)
    2. Telogen Effluvium
    3. Anagen Effluvium
    4. Systemic conditions (e.g. Hypothyroidism, Iron Deficiency Anemia, nutritional deficiency)
    5. Alopecia Totalis
  2. Focal or patchy - Nonscarring Alopecia (non-cicatrical Alopecia)
    1. Tinea Capitis
    2. Trichotillomania
    3. Traction Alopecia (e.g. tight braiding)
    4. Alopecia Areata
    5. Secondary Syphilis (Alopecia syphilitica with moth-eaten appearance)
  3. Focal or patchy - Scarring Alopecia (Cicatricial Alopecia, uncommon)
    1. Congenital defects
    2. Trauma
      1. Chemical agents (caustic substances)
      2. Burns
      3. Radiation
    3. Inflammatory dermatoses
      1. Discoid Lupus Erythematosis
      2. Sarcoidosis
      3. Lichen Planus follicularis
      4. Necrobiosis Lipoidica diabeticorum
    4. Infection
    5. Neoplasm
      1. Basal Cell Carcinoma
      2. Squamous Cell Carcinoma
      3. Metastases
      4. Lymphoma

III. History

  1. History of present illness
    1. Duration of Hair Loss
    2. Pattern of Hair Loss (see below)
    3. Progression of Hair Loss
  2. Family History of Hair Loss
    1. Androgenetic Alopecia
    2. Alopecia Areata
  3. Hair Loss type
    1. Broken hairs: Tinea Capitis, Trichotillomania
    2. Hairs lost by roots
  4. Concurrent systemic symptoms (e.g. weight loss, Fatigue) or systemic illness or endocrinopathy (e.g. Hypothyroidism)
    1. Alopecia Areata
    2. Telogen Effluvium
  5. Concurrent psychiatric illness or significant stress, pregnancy or febrile illness (with abrupt onset)
    1. Telogen Effluvium
    2. Trichotillomania
  6. Recent medication changes
    1. Telogen Effluvium
  7. Hyperandrogenism in women
    1. Androgenetic Alopecia
  8. Excessive hair care product use (straightening agents, Shampoos)
    1. Trichorrhexis Nodosa
  9. Nail changes
    1. Alopecia Areata (esp. Nail Pitting)

IV. Exam: Hair

  1. Hair distribution and areas of thinning
  2. Hair Pull Test
  3. Scalp scarring
    1. Inflammation
    2. Scaling
    3. Loss of Hair Follicles in non-scarring Alopecia
  4. Hair Shaft exam
    1. Hair length and caliber
    2. Hair fragility
  5. Scalp with Scaling, Pustules, crusts, erosions or erythema or local adenopathy
    1. Infection
  6. Dry, broken hair
    1. Trichorrhexis Nodosa

V. Signs: Patterns of Hair Loss

  1. M-Pattern in Men (bi-temporal, frontal, vertex) or central and vertex thinning (with spared frontal hair) in women
    1. Androgenetic Alopecia
  2. Diffuse Hair Loss
    1. Alopecia Areata (or if involves the entire body, Alopecia Totalis or universalis)
    2. Telogen Effluvium
    3. Toxin or Chemotherapy exposure
    4. Endocrinopathy
  3. Focal Hair Loss
    1. Traction Alopecia
    2. Trichotillomania
    3. Tinea Capitis
    4. Alopecia Areata
    5. Systemic Lupus Erythematosus
    6. Syphilis

VI. Labs

  1. Potassium Hydroxide (KOH) of scalp scraping
  2. Consider additional labs based on Alopecia type
    1. See Alopecia Areata
    2. See Androgenetic Alopecia
    3. See Telogen Effluvium
  3. Scalp Biopsy Indications (4 mm Punch Biopsy)
    1. Scarring Alopecia (not diagnostic if Trauma related)
    2. Unusual Hair Loss pattern

VII. Management

  1. Refer cicatrical Alopecia (scarring Alopecia)
  2. See specific Alopecia types for management

VIII. Resources

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