New longitudinal band in a light-skinned person

Sudden change in appearance of band (e.g., proximally wider, darker, blurred border)

Single-nail involvement (especially thumb, index finger, or great toe)

Pigmentation of the skin of the nail fold or proximal nail bed (i.e., Hutchinson’s sign)

New pigmentation in older persons (i.e., 60 to 79 years of age)

Band width of more than 3 mm

Family history of melanoma or dysplastic nevi

Abnormal nail structure (i.e., destruction or disruption of the nail plate)