An adverse toxic reaction to the topical application of a 2% boric acid solution is described in a 2-year-old girl. Topical boric acid is licensed for use in children above the age of 10 in the Czech Republic.
However, it can be bought over the counter and it is very often used in younger children. Due to its fast absorption and slow elimination, there is a high risk of systemic side effects.
On the other hand, topical side effects are not reported in the present literature.