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Brown mark under my big toe nail

I have a brown mark under my big toe nail, it's been there a while, and doesn't seem to go away. I've never worried about it before, but have recently read an article about cancer under the nail and was wondering if i should be concerned.

27 August 2019

This content was last reviewed and updated in August 2019 by Pedro Santos, a registered nurse in our Health at Hand team.

Hello, thank you for contacting us with your question. There are several reasons why we can see discolouring under the toe nail and usually it isn't a cause for concern. 

One of the most common reasons for this type of appearance are splinter haemorrhages. These are small bleeds from tiny vessels underneath the nail bed and will look like small brown streaks or lines underneath the nail, usually 2 to 5mm long.

Previous trauma to the nail or toe can also cause brown patches and their appearance is usually due to bleeding leading to the formation of haematomas, a collection of old blood which can appear as a small brown patch. 

Skin conditions such as psoriasis can also cause brown patches to form and occasionally fungal infections in the bed of the nail can cause this, although most fungal infections affect the nail bed itself.

Cancer under the nail is relatively rare - about 1.4% of the melanomas are of this type. This type of cancer is called subungual melanoma. We are enclosing a link where you can read more information about nails and their possible problems here:

Nail abnormalities - NHS

Under the circumstances we think it would be sensible to arrange have a chat with your GP. They will be able to examine the nail bed for you and both diagnose the problem and prescribe any treatment should it be needed.

We do hope this information will be of use, best of luck.

Answered by the Health at Hand team.  

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