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Line on left hand thumb
Hello Doctor,
I have this line on my left thumb. It is there as it is since around 8 months now. It has not grown darker or wider.
Would vitamin deficiency also cause this?
I am really worried. No history otherwise.
Please suggest. Attached are two photos. First from February and latter current one.
Answers (21)
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It looks like melancholia, a benign condition caused by increased melanin deposit. It can be caused by trauma, pregnancy, x ray exposure.
However if it increases in size, becomes painful , it needs to be evaluated.
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A single persistent line on the thumbnail (likely a vertical brown/black line) is usually called longitudinal melanonychia → Longitudinal Melanonychia
Next Steps
• No urgent treatment needed
Health Tips
• Avoid repeated trauma (nail biting, pressure)
• Maintain nail hygiene
• You can still check:
– Vitamin B12, iron (general health)
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It appears like melanonychia , usually a benign condition.if you find any change in appearance, colour,extension., consult a dermatologist in your area
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It seems like nail pterygium...just use topic lichensa ointment twice daily
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Usually these lines on the nails appear with iron and calcium deficiencies. If left unattended, the nails can become brittle too. Get your blood tests done for iron studies, haemogram, calcium, alkaline phosphotase, VIT D and review for further management
Next Steps
Get the tests done
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Please check liver function test ( LFT) including serum albumin as hypoalbuminemia can cause this sometimes.
Any other nails involved ? Need to rule out fungal infection.
Rare for any vitamin deficiency to cause this.
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A stable vertical line on the nail for months is harmless and not due to vitamin deficiency.
It can be due to minor trauma or pigmentation smoking can contribute.
No need to worry unless it increases in size, becomes darker, or spreads to surrounding skin.
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The thin vertical line on your thumb nail, which has been stable for 8 months without changing in width or color, is most likely a condition called Melanonychia. While vitamin deficiencies (especially B12) can sometimes cause nail discolorations, they usually present more diffusely. Since there is no history of sudden change or 'Hutchinson's sign' (extension of pigment to the nail fold), it is likely benign. However, any pigmented line on a single nail warrants a baseline clinical examination to rule out more serious causes."
Next Steps
Keep monitoring the line every few months. If you notice it becoming wider (especially more than 3mm), darker, or if the edges become blurred, you should consult a dermatologist immediately. For now, try to recall any minor trauma to the thumb base 8-10 months ago, as even small injuries can leave a lasting mark on the nail plate."
Health Tips
"Do not try to scrape or file the nail to remove the line, as the pigment originates from the nail matrix (under the skin) and not the surface. Avoid self-medicating with high-dose vitamins without a confirmed deficiency, as it won't resolve the line if the cause is non-nutritional. A simple dermoscopic examination by a specialist can provide 100% peace of mind."
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Don’t worry, it usually resolves on its own.
There are many possible reasons for this, but in your case are you on long-term antibiotics? If yes, that might be one of the causes.
Otherwise, it could be due to a vitamin deficiency (especially B12) or possibly related to trauma.
Next Steps
Try multivitamins for a month
And if it progresses more, than consult a Dermatologist
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Its self resolving. Minor changes may vary person to person. So no worry.
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Hi dear,
It is melanonychia. It is usually a benign condition usually followed by minor nail bed trauma due to melanin deposition. In your case it looks harmless as it does not reach nailfold/cuticle.
Next Steps
Be re-assured and just be watchful for any future changes in colouration/ darkening or widening of this line or if it reaches nail fold where nail originates.
Health Tips
Visit a dermatologist if in case it shows above mentioned changes. Rest be re-assured.
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No need to worry
Next Steps
Self limiting, you should look for causes where there is pressure application in nail base, e.g. Nail biting
Health Tips
If you do mechanical work you can work with cotton gloves
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Dr. Moin Ahmad Siddiqui
Trichologist
7 yrs exp
Lucknow
Normal
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Dr. Sohan Kulria
General Physician
5 yrs exp
Firozabad
If you want to discuss your problem in more detail, feel free to message me on WhatsApp at nine one one nine two five five six nine nine for a detailed discussion
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Dr. Gaurav Jaiswal
General Physician
6 yrs exp
Jhansi
Kindly do connect and consult
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Dr. Ravi Kumar Nadella
General Physician
18 yrs exp
Hyderabad
Start Candio
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Dr. Chaithra H
General Physician
5 yrs exp
Bangalore
Multivitamin deficiency
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Dr. Vetsa Sri Krishna Chaitanya
General Physician
7 yrs exp
Rajahmundry
Need a few more details please consult for further evaluation and treatment
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Dr. Suraj Sharma
General Practitioner
4 yrs exp
Jaipur
Do consult
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