Suggest Remedies For Breakouts Of Hives On The Body Of A Toddler

My 4 year old daughter started breaking out with random hives, or a rash Tuesday evening, it has stayed mostly on the back of her knees, but has presented itself on her waist, behind her ears, and her arms. Her knees hurt Tuesday, her ankles hurt yesterday, her left wrist and right big toe today. She is fine in the morning then gets weepy and complains about hurting, later in the day. She has a good appetite, and is sleeping well. She does have a strange, stiff like walk when the pain begins.