My son had a reaction (hives) in just one place. This has happened EXACTLY 5 times in the same spot. Is this common?

It is not entirely uncommon for someone to experience a reaction in the same place multiple times. In this case, it could be due to contact with an irritant causing a localized inflammatory reaction. It is important to observe any common factors that may be triggering these reactions, such as specific clothing or contact with animals. If the symptoms persist or worsen, it may be a good idea to consult with a healthcare professional for further evaluation and guidance on how to manage the situation.