Yep....rubber gloves when washing almost anything....and nail polish...at least 4 coats at all times.
Particularly stay away from stuff like Dawn dishwashing liquid and Bar keepers Friend cleanser.
The nail polish can be something clear, I like Sally Hansen Nail Protex.
Linda C

Thanks Linda C. So stay away from Dawn, the blue stuff? Thats exactly what I use. Whats in Dawn that is bad? I'll have to buy a different type of dish soap.

I got some gloves. Thanks

I have no idea what's in Dawn...but when ever I help out in the kitchen at someone's house that uses it...my nails split peel and break for a couple of weeks.
I think it's the de greaser....removes all the oils from your nails.
Linda C

I personally think it looks like a fungal infection. See your doctor, they can prescribe an antibiotic to treat it.

I did note that you said they did a test for fungus, but I would get a second opinion. I didn't get that in my first post!

Get another opinion from another dermatologist. It looks like either fungus or psoarasis of the nail beds.

Took my sister 3 dermatologists to get the right diagnosis and treatment. it was fungus on one hand and nails and psoarisis on the other. Both can be treated effectivley with the right meds.

"Some people advise to take prenatal vitamins for hair and nail growth"

Can I just say you should NEVER do this unless you are pregnant! Those vitamins contain enough for mother and baby.They are not intended for single person usage.
To prove my point,after I had my daughter,I continued to take mine for about 3 more months.I figured I probably could use the extra vitamins.
Then I went for a physical and my doctor was shocked at how high a level certain vitamins in my system were. She said I had so much iron I risked organ damage,and to stop taking the Prenatal vitamins right away.
I always tell people this because alot of young girls think taking them will make their hair grow faster too.They dont,and actually can harm you if you arent pregnant,so please beware.

It would be very close to impossible to overdose taking prenatal vitamins unless you were also taking another iron supplement and took both at once for a period.
Elements in prenatal vitamins can mask pernicious anemia, a condition concerning vitamin B 12 absorbtion more common with people of African Americans than Asians or southern European descent.
High iron levels in the blood are not caused by consuming too much iron. Too much oral iron compounds cause nausea, diarreha tarry stools.
If you had high iron levels in your blood to the point of risk, there was a lot more going on than just prenatal supplements.
Vitamins can affect your nails. If you are not taking a supplement which includes calcium or getting enough protein, that will affect your nails.
Linda C

The skin on the tips of my thumbs (not the nails) crack and bleed. I've found that applying vitamin E oil helps heal them.

Dawn dishwashing detergent is the bain of dermatologists. Linda, you are right. They say it is the degreaser that pulls out all the oils in your skin around your nails that causes the problems.
Docs suggest to only use it if you wear rubber gloves, otherwise "leave it on the shelf at the store and use something else.
I find that Joy works well and doesn't create the same kind of problem.

Also, using a little bit of a triple antibiotic ointment on those cracks in the skins around the fingernails will heal them very quickly. I've found it works much better than vit. E.
I find it can happen to my fingers in the winter when I wash may hands quite a bit while doing certain kinds of crafts.

That looks similar to something I had the summer after high school, it was the strangest thing. I was working as a cashier in a department store that summer and got the worst case of eczema (? never had it diagnosed) on all my fingers, and my nails got weirdly tough and flaky like yours look. My fingers itched and burned so bad and looked so bad that I wrapped them in a dozen bandaids every day. Later that year I healed myself of it and it has never returned. It was so bizarre...it came out of nowhere. I wish I could tell you what to do about it, but at least I can tell you I've seen it before.