Q. What causes blue and black lines on the toenail?

Answered by
Dr. Filza Hafeez
and medically reviewed by iCliniq medical review team.
This is a premium question & answer published on Dec 10, 2021

Hi doctor,

I did treadmill exercises and played tennis for two hours three weeks ago. And after that, I noticed blue and black lines on the fourth toe of my left foot. Can you tell me what this is? Is it melanoma?

I am worried and anxious.

Kindly help.



Welcome to

I need to see a clear picture of your lesion to make a diagnosis.


Hello doctor,

Thanks for the reply.

I have attached the pictures.

I removed some of the nails due to stress.




Welcome back to

I saw the pictures (attachments removed to protect the patient’s identity). You have removed almost all of the nail plate. So, take great care of the open nail bed, do not get it infected in any way. The nail images before removal show a horizontal band, which is free of any clinical sign of melanoma. Kindly let the nail plate grow back and get back to me after six months for re-evaluation.


Hi doctor,

Thank you for the reply.

I have some questions.

1 ) As you said, "horizontal band, which is free of any clinical sign of melanoma," why can it not be a melanoma?

2) What do you think could be the cause for the lines around the nail?

3) Is there any name for this condition?

4) If this was a melanoma, and if we remove them, will it come back again?

Thank you again.



Welcome back to

I will answer all your questions as follows;

Clinically, when we see any discoloration in the nail plate, we look for asymmetrical shapes, border irregularities, and color variations. If anyone of them is present, we step on to diascopic and dermoscopic examination. I have looked closely in your case, and there is no such abnormality in the shape, color, or border. There was a clear-cut horizontal band that was homogenous in color. So, in my opinion, it was trauma to the nail, as there is a very tight space below the nail plate, so blood cannot diffuse into the surrounding area. It remains very typical and regular shape.


Was this answer helpful?


Same symptoms doesn’t mean you have the same problem. Consult a doctor now!

Related Questions:
Is it fine to have no toe movement after foot injury while playing?

.. hear about the injury. The first thing you should do now is to take an X-ray for a safety case. Ignoring cannot be beneficial. Usually, the fracture is uncommon but still have to take an X-ray to rule out any fracture possibility. Also, for now, d...   Read full

I have a tiny spot under my toe nail after having an injury. Is it due to subungual blue nevus?

.. your concern. Though it looks like blue nevus, it is rare to occur in a subungual area in the acquired state (attachment removed to protect patient identity). Though it remains harmless. it can have a malignant transformation rarely. It is indicat...   Read full

Does radiation therapy increase the risk of melanoma?

.. therapy, the skin does suffer a burnt both immediate as well as on a long term. Dryness, itching leading to oozing and crusting are very common complaints after radiotherapy and can start as late as 15 to 20 years too after the treatment. Radiat...   Read full

Also Read Answers From:

ideaComprehensive Medical Second Opinion.Submit your Case

Also Read

Monkeypox Virus - Symptoms, Diagnosis, Treatment, Complications, and Prevention
Monkeypox is a zoonotic viral disease. This virus got its name as it was first noticed in laboratory monkeys in the late...  Read more»
Tomato Fever - Causes, Symptoms, Diagnosis, Treatment, and Prevention
Tomato fever is an unidentified and fast-spreading type of viral infection seen in young children. Scroll down to know m...  Read more»
Histrionic Personality Disorder - Causes, Signs, Symptoms, Diagnosis and Treatment
Histrionic personality disorder causes variations in the thinking ability of a person. Read this article to know more.  Read more»

Ask your health query to a doctor online?

Ask a Dermatologist Now

* guaranteed answer within 4 hours.

Disclaimer: No content published on this website is intended to be a substitute for professional medical diagnosis, advice or treatment by a trained physician. Seek advice from your physician or other qualified healthcare providers with questions you may have regarding your symptoms and medical condition for a complete medical diagnosis. Do not delay or disregard seeking professional medical advice because of something you have read on this website. Read our Editorial Process to know how we create content for health articles and queries.