Ingrown toenails in infants don’t occur very often, but it is possible. Most of the time it is either present at birth or appears soon after. The affected toe(s) become red, swollen, and painful. Inflammation may be accompanied by infection causing pus and drainage.
Not much is really known about this problem in children. There are many theories about the cause(s). A sharply curved or short nailbed may cause inflammation and then pain in the nailfold. The nailfold is the corner of the nail where the skin and soft tissue meet the nailbed.
Malalignment of the nail may also be an anatomic variation leading to ingrown nails. Shape, size, and alignment of the nailbed may be inherited. A family history of ingrown toenails suggests a hereditary factor.
Toe sucking and lying on the stomach may be contributing factors. Position in the uterus (mother’s womb) (especially with twins) could be a possible cause. And it’s likely that more than one factor present leads to eventual symptoms requiring treatment.