I remembered that my cat's nails were once cut too short at the shelter to a point where blood came out before I adopt her. I brought her home a month after that incident and that was 3 years ago. I notice some black debris in the inner rim of the claws, but I thought it's dirt. I always brush her nails during her monthly bath, but the debris never go away. I found that those are not only debris from the litter box, but also brown-dry-blood like build ups. Those buildups pushed the quick back to half of the width of the nail and the quick is a little red. It's on all of her front and back claws. Some of the nails are widely split because of this. Not until recently I realized this may be a problem after I saw a video of healthy cat nails. (Pictures of my cat's claw is attached)
She is a total in door cat. 3 years old. Takes shots from vet every year. Overall healthy. I feed her high quality cat food and home made meet. Trim her nails carefully every week. Never wound her. The nails are like that for 3 years and it doesn't seem bordering her except that she licks and pulls her claws occasionally. She uses her claws to play and jump without a problem.
I put All-Purpose Veterinary soothing Ointment(0.3% Hydroxyquinoline, Sulfate containing petrolatum, lanolin, cetyl alcohol) on her nails, but she licked it immediately. I don't know if it is safe.
I'll take her to vet for sure if necessary. But she's alway affect greatly from vet visit, so firstly I'm trying to find out how serious this is if it is a problem, and see if I can cure it at home. I searched everywhere but found very little information. Some articles suggested condition like this may be bacteria or fungus/yeast infection, but no one shows what it really look like. If anyone have seen similar conditions or knowledgeable about this matter please help. Thanks!