I have an 8 yr old daughter who has two fingernails, one on each hand, that are not smooth, they are slightly bumby and the
nail that grows out at the end is not uniform, curvy. They do not have complete horizontal ridges across them. Sort of like moguls on a ski slope. They are not discolored and it only occurs in those two fingernails.
She has had this for close to a year. She's rarely sick and if it was nail fungus I would think it would have spread to her other nails.