Vertical brown-black nail lines (longitudinal melanonychia): Indications for referral
| Any new vertical brown-black nail lines in a fair-skinned patient |
| Vertical brown-black lines on a single nail, in any patient |
| Any history of change in the brown-black lines or bands (darkening, widening, bleeding) |
| Width of brown-black lines greater than 6 mm |
| Proximal width greater than distal width |
| Heterogeneous color |
| Indistinct borders |
| Associated nail fold pigment (Hutchinson sign) |
| Associated nail plate dystrophy |
| Associated bleeding |
| Associated ulceration |
| High-risk digit (thumb, index finger, great toe) |
| Personal or family history of melanoma |