The nail change top dermatologists BEG patients not to ignore... as it could be a sign of aggressive skin cancer

A top dermatologist has warned patients to pay close attention to their nail beds, as a subtle change could indicate melanoma — the deadliest form of skin cancer.

Dermatologist Lindsey Zubritsky, who goes by @dermguru on Instagram, warned her 1.2million followers to watch out for the streaky dark marks under the bed of the finger and toe nails.

'If you have a dark pigmented vertical streak going down your nail, this absolutely should be checked,' she said. 

That's because the dark lines could be a subungual melanoma — a rare type of the disease that develops under the nail.

This type of the condition can be easily missed, as the telltale sign is often mistaken for a bruise, Dr Zubritsky warns. 

Dermatologist Lindsey Zubritsky, or @dermguru on Instagram, warned her 1.2million followers to watch out for the streaky dark marks under nails, which could be a type of melanoma

The dark lines could be a subungual melanoma — a rare type of skin cancer that develops under the nail

Subungual melanomas commonly appear as a dark brown or black streak.

The nail may also become thicker, separate from the nail bed and split down the middle.

Another concerning sign of the disease — which accounts for around one in 30 melanoma cases — is if pigmentation starts to creep up and discolor the skin beyond the nail.

But if the thickness of the nail changes, and becomes yellowed, it could be another type of nail cancer called onychomatricoma. 

Subungual melanomas commonly appear as a dark brown or black streak. The nail may also become thicker, separate from the nail bed and split down the middle due to the cancer, which accounts for around one in 30 melanoma cases

Not all dark streaks on the nail are dangerous, many people have a benign streak, she explains

But black spots and streaks are not necessarily a sign of cancer.

Most commonly, they are a sign of a skin condition, wart or microtrauma — a painless injury that can occur due to your toe repeatedly hitting against your shoe. 

It could also be harmless pigmentation, called longitudinal melanonychia. 

'Not all dark streaks on the nail are dangerous, many people have a benign streak on their nail called longitudinal melanonychia, which is totally normal,' Dr Zubritsky adds in the video. 

'It's more likely to be benign if it is lighter, it's not changing in colour, it's found on multiple nails or you have a darker skin tone,' she said. 

It should also not be mistaken for a subungual hematoma, which is when you have blood trapped under the nail and it typically grows out with time, she added. 

But Dr Zubritsky 'begged' her followers to 'see a dermatologist if you have anything new or changing on your skin, and don’t forget to check your nails.'