Dark lines on nails

I think I have found out the reason. I have a faint black vertical line on my right trump as described by kymoon. I don't think this is cancerous as the symptom is a lot darker and thicker. So one of the very last comment here inspired me that it could be some sort of vitamin deficiency and guess what have I found !? Vitamin C deficiency Splinter haemorrhages can be seen in scurvy though they are classically associated with subacute bacterial endocarditis and are most frequently caused by trauma. They are formed by extravasation of red blood cells from longitudinally oriented nail bed vessels into adjacent longitudinally oriented troughs. They appear as red to black thin longitudinal lines under the nail-plate. Vitamin C deficiency has also been associated with koilonychia and hapalonychia. Time to take some supplement!!

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I am of Asian descent, and noticed both my Dad and his mother had dark lines down most of their nails. I get a dark line on several of my fingernails when I eat cabbage or brussel sprouts. They go away after a few months if I don't eat them again. Not sure if other foods make me react the same. I read somewhere decades ago that the high sulfur content could do that. Don't know how accurate that is.

I have same lines in my thumbnails. I started to notice these after giving birth. I haven't paid much attention to the lines since I'm also suffering from carpal tunnel syndrom from the recent pregnancy. I thought it could be because of the veins that are affected by CTS.

Go check a doctor

I have the same problem! I gave birth 1 month ago and had carpal tunnel since my 38th week pregnancy (still have in my left thumb). Just today (1 month postpartum) I noticed a faint light brown vertical line across my left thumb accompanied by a sharp pain when lithely touched at the tip of that thumb. Have an OB visit in 2 weeks, will ask her.

Is it benign?

It's certainly not malign. I have had mine for 1 year now, they've never gotten any worse or any better, they're just there, faint gray lines in a few of my fingernails. Shows it isn't melanoma: faint (not black), and several digits (as it's highly unlikely melanoma will show up in more than 1 finger at a time). I recently saw someone's unrelated picture online and couldn't help but notices those same lines, I had to ask, as I don't know anyone else who has them. She's asian, and she said she's had them for years and her husband does too. Doesn't know what cause them but could be a vitamin deficiency, hormones, a medication, or who knows. But nothing to be scared of, as I was when I found them and newly fainted when I read about melanoma and ended up at the drs office. Thank God everything pointed away from that.

I have the same after pregnancy

I too have this line on my left thumb nail. I am going to make a GP appointment. I do have Addisons and Graves disease so I am wondering if it could be because of my pigmentation levels. Hope your find the answers.

Me too..so nervous

It same with me :( now im 34 years old

I have exactly the same. First it was on the right side edge of my right hand index finger. Had it for years. Now I have it on my my right thumb too and one is also appearing on my left thumb. I must point out though, that I do have fungal infection on my toe nails which I'm treating. I wash my hands thoroughly after treating or touching my feet or toes. My thought was perhaps the fungal infection from my toe nails may havery gotten to my finger nails - just a thought and not sure of that really is the case. Its been like this for years. It never bothered me much before. Bit because it's appearing on my other nails now, I'm going to get it checked with my doctor. I'll reply to you again when I know more.

Hi, any news? I have these lines too since my 20s but it suddenly became more on my third trimester during my layest 2nd pregnancy... am so nervous while waiting for the derma's appointment next week... Do update!

I had the same recently. Im 18 years old and relatively healthy I noticed that i had had a few very faint grey lines on my left and right thumb nail. I initially googled "Line under nails" and the internet was throwing the word melanoma at me; obviously this caused me to have several panic attacks. I went to the doctors a couple days later because i also had a mole i'd never seen before which was also causing me panic and it was on my left hand, index finger. I showed her and she instantly said you should never google what you have because it will cause you unecessary stress and will always give you the worst case scenario. She also confirmed the mole looked normal and its normal to get streaks on your nails. My mum who was also with me said she would be able to tell if it was anything servere because she saw how panicked i was, i couldnt even eat dinner the night i googled about the lines on nails. Now that i have read a few posts on here im guessing im either lacking vitamins or going through hormonal changes as i am an 18 year old male. If any of you are worried, go to a doctor but i guess it's rare for skin cancer to just randomly show up in 2 different digits on 2 different hands.

This was literally me when I made the mistake of googling my symptoms. I was worried sick to the point of almost vomiting. I couldn't get an appt until like 3-4 days later and I was sooo worried those days and nights. I also have it in 3 fingers so my husband who did a way better and deeper search found that melanoma doesn't work that way. He was trying to be reassuring but it wasn't until an actual doctor looked at it that I had peace of mind.