Hives can formulate on your skin due to a number of reasons. Many of which require that you be exposed to a physical stimuli. These can be things like sun exposure, heat exposure, cold exposure, insect bites, insect stings, certain foods, and tons of more stimuli.
Each person reacts differently to various stimuli. Some people may be allergic to nuts, while others can eat a bunch of them without any physical reaction. You know you have an allergic reaction when your skin breaks out in red itchy welts. These can breakout anywhere on the body, and will typically move from one place to another.
Hives are very unpredictable as to where they formulate on the body, and where they move to. Sometimes they can start small and then adjoin with other areas of the infection. This can create a massive sized section of raised welts all over the skin. If the welts are itchy you can be sure they are hives.
Many people wonder can you catch urticaria? The truth is that you can’t. This isn’t an infection that can be passed on from one person to the next. This is solely a response from the body due to stimuli. There is no physical way to get someone else’s hives infection.