- Subungual hematoma, a bruising beneath the nail which lacks the uniformity of subungual melanoma
- Fungal infections (onychomycosis) which more often have dark, non-longitudinal stripes accompanied by yellow or white streaks
- Moles (nevi), which are less likely to appear in streaks
- Deposits of melanin beneath the nail which can occur as a result of pregnancy (as well as chemotherapy or radiation therapy)
In order to get a proper diagnosis of subungual melanoma, your dermatologist will carefully inspect the nail and lesion using a tool called a dermascope, which provides a magnified view of the nail and surrounding tissue.
In order to get a definitive diagnosis, you will need to have the entire lesion plus some of the surrounding tissue removed. This is called a biopsy. A less-invasive punch biopsy may be used if the signs are uncertain.
