Another problem with diagnosing hives is that the symptoms are relatively generic -- red, itchy welts on your skin are a common symptom among many skin disorders. Hives can be caused from allergens as well as physical and environmental factors such as stress, heat, sunlight or water.Are Hives always caused by an allergy?
While an allergic reaction can be a cause of hives, in the majority of outbreaks, the exact cause of hives is not known. Hives are also known as urticaria. Hives form when a chemical called histamine is released by specialized cells known as mast cells.