Hives, also known as urticaria, presents with a rash that is itchy and often appears like a giant mosquito bite. Typical hives do usually appear and settle within minutes to hours. The appearance of hives is not specific, and there are a number of skin disorders that can also mimic hives.
Conditions such as urticarial vasculitis and urticarial dermatitis can also present like hives, as can some viral induced rashes. However, these rashes usually last for more than 24 hours.
Typical hives or urticaria generally respond well to antihistamines. If the rashes are persistent, it would be a good idea to see your dermatologist or doctor to get it further evaluated and treated.