What type of reaction leads to the formation of hives?

The formation of hives, also known as urticaria, is primarily caused by an allergic reaction. When the body encounters an allergen, the immune system can respond by releasing histamine and other chemicals. Histamine is a powerful compound that causes blood vessels to dilate and the skin to swell, leading to the characteristic raised, itchy welts associated with hives.

In this context, the other options involve very different mechanisms of action that do not typically result in the formation of hives. A bacterial infection, such as one caused by Staphylococcus, can lead to other skin conditions but is not directly associated with the histamine release that causes hives. Similarly, viral infections, including those from herpes simplex, primarily manifest in different symptomatology and do not lead to hives. Lastly, infections from fungi like Candida Albicans are associated with specific conditions such as thrush or skin rashes but do not involve the allergic response that results in hives. Therefore, the primary mechanism leading to the formation of hives is indeed an allergic reaction triggered by histamine.