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What Causes Longitudinal Melanonychia?

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Posted on Mon, 1 Jun 2015
Question: Since December 2014, I've had a longtitudional Grayish - Black band running from the base of the nail to its tip, on the little finger of my right hand. It seems to have stayed consistent in its width (around 1 mm). A much paler version of this band and also much thinner (less than 0.5mm) has also appeared around the same time on the thumb nail (runnin from base of the nail to the tip) of my left hand. I had got myself checked up by a dermatologist who prescribed a routine Urine test and CBC test - both of these came out to be normal. He prescribed Limcee (Vitamin C) but till date, the bands have stayed on - they neither seemed to have thickened or blackened nor shrunk or become lighter. I believe they've stayed 'AS-IS' - the dermatologist prescribed certain steroid injnections (21 were recommeneded to be adminstered one after the other in sequence - I don't know which specific injection was it) but I refused. The dermatologist had mentioned that in case the band doesn't go away even after these injections, he would recommend a nail biopsy. This was one year back - since then, I've discontinued the check-up by that dermatologist. Please advise.
doctor
Answered by Dr. Dr. Kakkar (1 hour later)
Brief Answer:
Upload an Image; provide more details

Detailed Answer:
Hello. Thank you for writing to us

I have taken note of your query and I have understood your concern.

The condition which you have is known as, longituinal melanonychia.

The important points that I could gather from your history is that there is a longitudinal band of pigmentation that is present along the whole length of nail, on right little finger, is 1 mm wide and has stayed as it is, since you noticed it first 4-5 months back.

Another similar but fainter band of 0.5 mm width, on the left thumb nail.

Longitudinal Melanonychia can arise as a result of both benign and malignant conditions.

Benign conditions that can give rise to linear well defined melanonychia band can be... racial; nail trauma; skin conditions like psoriasis, lichen planus; certain drugs; nail matrix nevus etc
Malignant cause includes nail matrix melanoma.

A biopsy of the nail matrix is what I would suggest to rule out a possibility of Melanoma with certainty, specially since it affects only a single nail, has arisen in 5th decade.
There should be a low threshold for biopsy in a white male who presents with a single isolated band in 4th or 5 th decade.
Though points against a melanoma are that it hasn't changed, is less than 3 mm wide, involves little finger rather than thumb or index finger.

I would request you to upload a clear digital Image so that I am able to guide you better.

You can upload an Image either at "Reports Section"

Or

You may also mail me at YYYY@YYYY with the subject of this mail as Attn:Dr. Kakkar

-I would also like to notice that whether it is uniform color Or has color variegation i.e brown and black areas?
-Whether it has regular borders Or blurred borders?
-Is there any family history of melanoma?

Regards
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
doctor
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Follow up: Dr. Dr. Kakkar (1 hour later)
Thanks for your prompt response Dr. Kakkar. I've attached the snaps of the nail bands for both the left hand thumb nail and right hand little finger's nail. One correction to your observation - this condition on the right little finger's nail is existing since mid-Dec'2014 - at least that's when I first observed it and even though the width of the band has remained around or just less than 1 mm, to the naked eye, it sometimes seems as though it has broadened. However, since Dec'14, I've been measuring the width with a scale and actual measurement by the scale only leads to the determination that the width has stayed around 1mm.. I did not understand your statement that there should be a low threshold for biopsy in a white male who presents with a single isolated band in the 4th or 5th decade - could you please elaborate further on this?

Is this sort of biopsy painful and will it lead to loss of nail? How much would it typically cost?

I am sorry for the confusion - I mentioned that the longtitudional band first appeared / was noticed in Dec'14. I meant Dec'13. So, that makes it 1.5 years almost since the band has been there in my knowledge, on the nail of my right little finger. The band on the right thumb's nail has also, more or less, been around for the same time. It got noticed only after I had noticed the right little finger's nail band - probably as a result of my scanning all my nails thereafter regularly with more detail and scrutiny
doctor
Answered by Dr. Dr. Kakkar (2 hours later)
Brief Answer:
Unlikely to be a melanoma; A biopsy would be confirmatory

Detailed Answer:
Hi.

I have reviewed the Images. There is a band on both the digits.
As far as I can see there is a well defined, homogeneously colored, longitudinal band of pigmentation with no variation in width of the band.
The overlying nail plate is intact.

This could be racial Or due to unnoticed trauma Or other benign causes like a lentigo Or nail matrix nevus.
Moreover, the band has not changed in appearance since you last noticed it in dec'13.
A single digit involvement, particularly if present in thumb, index finger and great toe is more suspicious of a melanoma.
Therefore this is unlikely to be due to melanoma, specially since it involves more than a single digit.

Melanoma is more common in whites/ caucasians therefore there should be a low threshold for biopsy in whites, who present with suspicious looking longitudinal melanonychia.

A wait and watch approach is justified in your case.

However, a biopsy would be conclusive. The cost of a biopsy would vary from anywhere between 35-50$. It would be done under local anesthesia. The nail would be lost.

Regards
Note: Hope the answers resolves your concerns, however for further guidance of skin related queries consult our Dermatologist.Click here to book a consultation

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
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Answered by
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Dr. Dr. Kakkar

Dermatologist

Practicing since :2002

Answered : 9612 Questions

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What Causes Longitudinal Melanonychia?

Brief Answer: Upload an Image; provide more details Detailed Answer: Hello. Thank you for writing to us I have taken note of your query and I have understood your concern. The condition which you have is known as, longituinal melanonychia. The important points that I could gather from your history is that there is a longitudinal band of pigmentation that is present along the whole length of nail, on right little finger, is 1 mm wide and has stayed as it is, since you noticed it first 4-5 months back. Another similar but fainter band of 0.5 mm width, on the left thumb nail. Longitudinal Melanonychia can arise as a result of both benign and malignant conditions. Benign conditions that can give rise to linear well defined melanonychia band can be... racial; nail trauma; skin conditions like psoriasis, lichen planus; certain drugs; nail matrix nevus etc Malignant cause includes nail matrix melanoma. A biopsy of the nail matrix is what I would suggest to rule out a possibility of Melanoma with certainty, specially since it affects only a single nail, has arisen in 5th decade. There should be a low threshold for biopsy in a white male who presents with a single isolated band in 4th or 5 th decade. Though points against a melanoma are that it hasn't changed, is less than 3 mm wide, involves little finger rather than thumb or index finger. I would request you to upload a clear digital Image so that I am able to guide you better. You can upload an Image either at "Reports Section" Or You may also mail me at YYYY@YYYY with the subject of this mail as Attn:Dr. Kakkar -I would also like to notice that whether it is uniform color Or has color variegation i.e brown and black areas? -Whether it has regular borders Or blurred borders? -Is there any family history of melanoma? Regards