Hives (also called urticaria) are red, itchy welts that appear on the skin following a reaction. The welts appear rapidly and continue to appear and disappear as the reaction runs its course. The size and location of the welts usually change as this happens. The cause of hives is not always clear. Hives may be caused by anything from a virus to an allergen. It could also be due to hormonal change, temperature change, insect bites, or stressful situations. These are all known as triggers.
Hives may be chronic or acute. Chronic hives are generally those that last over six weeks and recur frequently. According to the American College of Allergy, Asthma and Immunology  (ACAAI), the symptoms can last anywhere from a few minutes to a few years. This article explains the most common hive symptoms so you can differentiate them from other dermal reactions.
Blanching of the welts
Differentiating welts caused by hives from other kinds of dermal conditions is tricky. Welts associated with urticaria usually blanch when pressed. According to the American College of Allergy, Asthma and Immunology  (ACAAI), the center of a red hive usually turns pale or white when you press it. This is more noticeable on white skin. On darker skin, you may only notice a reduction in the redness of the welt.