Yes, the light brown vertical line on your big toenail CAN be melanoma, says a dermatologist.
So let’s say that you just noticed a light brown vertical line on your big toenail (or any nail, for that matter).
“If you notice a vertical brown line on a fingernail or toenail, do not ignore,” begins Kally Papantoniou, MD, FAAD, with Simply Dermatology in NY.
Dr. Kally, as she is known by her patients, continues: “This can represent a benign mole that is occurring within the nail bed or nail matrix where the nail is being formed, but it takes a professional to distinguish the features of a benign vs. malignant growth.”
Even if you already know that the vertical brownish line of melanoma typically stretches into the skin at the base of the nail, you should still have the nail examined.
“Melanoma which occurs on the nail can be aggressive and it is important to make this diagnosis as early as possible,” says Dr. Kally.
“If there are multiple bands which appear to be monomorphic it is a good sign that these are benign, and these tend to occur more often in skin of color.”
Monomorphic means that the bands all have the same appearance.
“Occasionally it is not even a mole, but something called a splinter hemorrhage which occurs after trauma to a digit resulting in small amount of blood trapped under the nail.
“A splinter hemorrhage will grow out as the nail grows, whereas a melanocytic lesion will not grow out.”
Check your toenails and fingernails regularly for brown (or blackish) vertical lines.
Melanoma that looks like this will not suddenly appear overnight, whereas these splinter hemorrhages do appear soon after the trauma—and they can linger for quite a while, sometimes weeks.
A splinter hemorrhage will not progressively get bigger, while an untreated melanoma, after only four weeks, will show progression.
Dr. Papantoniou is a board certified dermatologist specializing in cosmetic, laser and surgical dermatology.
Lorra Garrick has been covering medical, fitness and cybersecurity topics for many years, having written thousands of articles for print magazines and websites, including as a ghostwriter. She’s also a former ACE-certified personal trainer.