What common factor increases the risk of bacterial skin infections?

Having a cut or scratch on the skin significantly increases the risk of bacterial skin infections because these breaks in the skin provide an entry point for bacteria. The skin acts as a natural barrier protecting the body from pathogens, and any disruption—such as a cut, scratch, or abrasion—compromises this defense mechanism. When the skin is broken, bacteria from the environment or even from the skin's own flora can invade and lead to an infection.

In contrast, while being in a warm climate, experiencing dry skin conditions, and exposure to high humidity levels can play a role in skin health and potentially impact the skin's barrier function, they do not directly provide a pathway for bacteria to enter the body as a cut or scratch does. Warm climates may encourage bacterial growth, and high humidity can lead to skin conditions that may increase vulnerability, yet none of these factors are as immediate or direct as a physical breach in the skin integrity. Therefore, having a cut or scratch is the most clear and direct factor that elevates the risk of developing bacterial skin infections.