• See Also
  1. Androgenic Alopecia
  2. Telogen Effluvium
  3. Anagen Effluvium
  4. Traction Alopecia
  5. Alopecia Areata
  6. Trichorrhexis Nodosa
  7. Hair
  • Physiology
  1. See Hair
  • Causes
  1. Diffuse Hair Loss
    1. Telogen Effluvium
    2. Anagen Effluvium
    3. Systemic conditions (e.g. Hypothyroidism, Iron Deficiency Anemia, nutritional deficiency)
    4. Alopecia Totalis
  2. Patterned Hair Loss
    1. Androgenetic Alopecia
      1. Male-Patterned Hair Loss (M-patterned hair thinning)
      2. Female-Patterned Hair Loss (central hair thinning)
  3. Focal or patchy Hair Loss - Nonscarring Alopecia (non-cicatrical Alopecia)
    1. Tinea Capitis
      1. Most common cause of Hair Loss in children
      2. Slow evolving scaly, pruritic patches of Hair Loss
    2. Trichotillomania
    3. Traction Alopecia (e.g. tight braiding)
    4. Alopecia Areata
    5. Secondary Syphilis (Alopecia syphilitica with moth-eaten appearance)
  4. Focal or patchy Hair Loss - 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
  • History
  1. History of present illness
    1. Duration of Hair Loss
    2. Pattern of Hair Loss (see causes above, and signs 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. Tight hair braiding
    1. Traction Alopecia
  10. Nail changes
    1. Alopecia Areata (esp. Nail Pitting)
  1. Diagnostics
    1. Hair distribution and areas of thinning
    2. Hair Pull Test
    3. Trichoscopy (dermatology)
    4. Dermoscopy (dermatology)
  2. Scalp scarring
    1. Inflammation
    2. Scaling
    3. Loss of Hair Follicles in non-scarring Alopecia
  3. Hair Shaft exam
    1. Hair length and caliber
    2. Hair fragility
  4. Scalp with Scaling, Pustules, crusts, erosions or erythema or local adenopathy
    1. Infection
  5. Dry, broken hair
    1. Trichorrhexis Nodosa
  • Signs
  • Patterns of Hair Loss
  1. See causes above
  2. Patterned
    1. Androgenetic Alopecia
      1. Men: M-Pattern (bi-temporal, frontal, vertex)
      2. Women: Central and vertex thinning (with spared frontal hair)
  3. Diffuse Hair Loss
    1. Alopecia Areata (if involves the entire body, Alopecia Totalis or universalis)
    2. Telogen Effluvium
    3. Toxin or Chemotherapy exposure
    4. Endocrinopathy
  4. Focal Hair Loss
    1. Traction Alopecia (esp. loss along the hair line)
    2. Trichotillomania (irregularly shaped patches of Hair Loss)
    3. Tinea Capitis
    4. Alopecia Areata
    5. Systemic Lupus Erythematosus
    6. Syphilis
  • Labs
  1. Potassium Hydroxide (KOH) of scalp scraping
    1. Tinea Capitis
  2. Microscopy
    1. Telogen hairs (club-shaped hairs)
      1. Telogen Effluvium
    2. AnagenHairs (inner root sheath still attached)
      1. Anagen Effluvium
    3. Exclamation Point Hairs (club Hair Root, thinned proximal Hair Shaft, normal distal Hair Shaft)
      1. Alopecia Areata
  3. Consider additional labs based on Alopecia type (e.g. TSH, Hgb, LFTs)
    1. See Alopecia Areata
    2. See Androgenetic Alopecia
    3. See Telogen Effluvium
  4. Scalp Biopsy Indications (4 mm Punch Biopsy)
    1. Scarring Alopecia (not diagnostic if Trauma related)
    2. Unusual Hair Loss pattern
  • Management
  1. Refer cicatrical Alopecia (scarring Alopecia)
  2. See specific Alopecia types for management
  • Resources
  1. National Alopecia Areata Foundation
    1. http://www.alopeciaareata.com
  • References
  1. Dakkak (2024) Am Fam Physician 110(3): 243-50 [PubMed]
  2. Nielson (1995) Am Fam Physician 51:1513-28 [PubMed]
  3. Phillips (2017) Am Fam Physician 96(6): 371-8 [PubMed]
  4. Price (1999) N Engl J Med 341:964-73 [PubMed]
  5. Shapiro (2000) Can Fam Physician 46:1469-77 [PubMed]
  6. Sperling (1998) Med Clin North Am 82:1155-69 [PubMed]
  7. Springer (2003) Am Fam Physician 68(1):93-102 [PubMed]