The first thing to consider in children with cracked fingernails is whether they have a nail biting fetish and whether it is caused by habits such as playing in the sand, or if they have a trauma-induced nail disease that can lead to cracked fingernails.
After these two possibilities have been ruled out, it is important to consider whether the nail is congenitally malnourished, or whether the intake of vitamins and minerals (e.g. calcium) is insufficient. Once these common causes have been ruled out, the cause of cracked fingernails in children needs to be considered in terms of other skin conditions and systemic diseases.