II. Definitions

  1. Chromonychia (dyschromia)
    1. Color changes of nails

III. Causes: White Nail - Leukonychia (partial or complete)

  1. Anemia (most common)
  2. Congenital (Autosomal Dominant)
    1. Abnormal keratinization of underlying nail matrix
    2. Results in nail plate white discoloration of one or multiple nails with all or partial nail involvement
    3. No Clinical Significance (normal variant in adults and children)
  3. Terry's Nails (all White Nails except the distal 1-2 mm nail edge)
    1. Chronic Liver Disease
    2. May also occur with Diabetes Mellitus, Congestive Heart Failure, Hyperthyroidism, Aging
  4. Half and Half Nails (Lindsay's Nails, white proximal, pink/red distal)
    1. Chronic Renal Failure
  5. Transverse Linear Nail Lesions
    1. Muehrcke's Lines
    2. Mees' Lines
    3. Transverse striate Leukonychia (white lines)
      1. Minor nail matrix or cuticle Trauma
  6. Leukonychia punctata (white spots)
    1. Minor Trauma to Nail Cuticle or matrix

IV. Causes: Miscellaneous Color Changes

V. Causes: Blue Nails

VI. Causes: Diffusely Black Nails (Melanonychia), Hyperpigmentation or Dark Longitudinal Streaks

  1. See Nail Abnormality (includes other longitudinal striations)
  2. See Hyperpigmentation
  3. Nail Hyperpigmentation is common
    1. Black patients have a 75% Prevalence of benign Nail Hyperpigmentation
    2. However, involvement of a single nail (esp. first), and esp. in a linear arrangement is concerning
      1. Represents Subungual Melanoma in 5% of caucasian and 15-20% of black, asian
  4. Subungual Melanoma
    1. Most important diagnosis to exclude (esp. if isolated, single nail involvement)
  5. Vertical Nail Bands (Longitudinal Melanonychia)
    1. Hyperpigmented bands occur as normal variant in 90% of black patients
    2. Distinguish from Subungual Melanoma (see below)
  6. Melanonychia striata
    1. Common in dark skinned persons
    2. Spontaneous or secondary to Trauma or Chemotherapy
  7. Benign Nevus
    1. Uniform brown longitudinal streak localized to nail
  8. Chronic Renal Failure
    1. Distal nail bed discolored brown
  9. Melanoderma
    1. Diffuse skin Hyperpigmentation may also affect the nails
  10. Other Causes
    1. Hyperpigmentation in Pregnancy
    2. Nutritional Deficiency
      1. Vitamin B12 Deficiency
      2. Folate Deficiency
    3. Miscellaneous Medication Side Effects
      1. Excessive Fluoride Supplementation (Fluorosis)
      2. Antimalarials
      3. Phenytoin
      4. Tetracycline
    4. Chemotherapeutics
      1. Cyclophosphamide (Cytoxan)
      2. Hydroxyurea
      3. Fluorouracil
    5. Connective Tissue Disease
      1. Systemic Lupus Erythematosus
      2. Scleroderma
    6. Endocrinopathy
      1. Addison Disease
      2. Cushing Syndrome
      3. Hypothyroidism

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