3 yr f has a chilblain on toe should i worry about lupus / or underlying condition . she seems healthy . led saw her said idiopathic sometime help?

Blood tests.: It is most likely idiopathic, but if he/she were my child i would go to the pediatrician and discuss some simple blood tests to try and rule out other possibilities, just to be sure.

Genetic orNeurologic: To probe deeper, this could be due to a genetic (e.g., aicardi-goutieres syndrome) or neurologic problem (e.g., cree encephalitis or pseudo-torch syndrome). Thus, you may also consider seeing a geneticist and/or a neurologist.