I had one that sucked her thumb while she was sleeping to the point that she had red oozing sores above the knuckle on both thumbs .... I pointed it out to the parents that I thought her thumbs were infected ... They took her to the dr and he put her on antibiotics and told them to put mittens on her when she went to bed to break the habit .... So that's what we both did and she no longer sucks her thumb