8 years old Baby Girl only one portion of this hand is effected from Vitiligo

8 years old Baby Girl only one portion of this hand is effected from Vitiligo,No Family history of this disease or no any other symptoms of any disease are present,So what should be done in that any possible cause?

Work up is usually negative but still must be done. The new topical jak inhibitor may work but I haven’t tried it yet. Nothing else really works.

Vitiligo acral, melanocyt transformation