As reported by the Courier, 10-year-old Bonnie Pullan, from Skircoat Green, began losing her hair three years ago after being picked on in the playground.
Doctors diagnosed her alopecia, brought on by the stress of being bullied.
Bonnie and her family, who have been strong supporters of Alopecia UK - raising £1,300 for the charity, launched an appeal last week to raise £5,000 for a pioneering treatment they hope will give her back the confidence she has lost.
Just a few days into the fundraiser, an anonymous donor has come forward pledging £4,000 so that they now have enough to pay for the treatment.
Posting on social media, Bonnie's stunned mum Wendy said: “Wow, an online donation of £4,000 and we’ve done it. Raised the full amount and Bonnie will get her hair piece.”