II. Epidemiology
- Normal variant in 90% of black patients
- Uncommon in lighter skinned patients
III. Signs
- Hyperpigmented longitudinal band (brown, black or tan coloration)
- Nonblanchable
- Typically spans the entire length of nail
- May affect one or multiple nails
IV. Risk Factors
- Most common in black patients
- See Hyperpigmentation
V. Differential Diagnosis
- See Melanonychia
- See Nail Longitudinal Band
-
Nail Splinter Hemorrhage
- Do not span the entire longitudinal length of the nail bed
-
Subungual Melanoma (50% of Melanomas in dark skinned patients)
- Critical to distinguish from the benign vertical nail bands
- Most commonly affects the great toe or thumb
- Bands are typically wider than 3 mm
VI. Evaluation
- Biopsy suspicious Longitudinal Melanonychia