Acute Allergic Reaction (Urticaria): This is the most common cause of hives in children, often triggered by allergic reactions to foods, insect bites, or medications. The sudden onset of itchy, raised wheals is characteristic.

Insect Bite or Sting: Reactions to insect bites or stings can cause hives, especially if the child has been outdoors.
Viral Exanthem: Many viral infections can cause rashes that resemble hives, such as enterovirus or respiratory viruses.
Food Allergy: Common food allergens like peanuts, tree nuts, fish, shellfish, milk, eggs, wheat, and soy can cause hives in allergic children.
Drug Reaction: Certain medications, including antibiotics and NSAIDs, can induce allergic reactions leading to hives.

Anaphylaxis: A severe, life-threatening allergic reaction that can cause hives, along with other symptoms like swelling, difficulty breathing, and a drop in blood pressure. Immediate recognition and treatment are crucial.
Mastocytosis: A condition characterized by an accumulation of mast cells in the skin, which can cause hives and other systemic symptoms.
Autoimmune Disorders (e.g., Lupus, Thyroiditis): Although rare in children, these conditions can present with skin manifestations like hives.

Urticarial Vasculitis: An inflammation of the blood vessels that can cause hives, but it's more commonly associated with systemic symptoms and is rare in children.
Hereditary Angioedema: A genetic disorder that causes recurrent episodes of severe swelling, which can sometimes be confused with hives.
Erythema Multiforme: A skin condition characterized by target lesions, which can be mistaken for hives, often triggered by infections or medications.