Fingernails splitting horizontally at cuticle - 3 yr old

[JeuxDEnfants]

Just wondered if anyone had any ideas? Most of his nails are split, just started in last 2 weeks out of nowhere. Should I take him to GP or just see how it goes? One of his fingernails has repeatedly split, so not sure it's just going to stop...

My 1 yr old had this randomly for a couple of weeks. I did some googling and seems it may occur after hand foot and mouth or other viruses which have a skin rash. My ds had recently had chick pox so thought it may be tgat. Anyway it went after couple of weeks