Boils are usually small areas (penny or nickel size) with a thin covering of skin, while abscesses are larger raised areas on the skin that are tender to touch and filled with pus in the deeper tissue. Abscesses and boils may drain when the skin over the infected area opens and lets the fluid or pus out. Signs of cellulitis include areas of redness, skin tenderness, and fever. All of these skin infections are usually warmer than the surrounding normal areas of skin because of the body’s reaction to the infection. Person-to-person contact with pus and skin bacteria and to a lesser extent, contaminated environmental surfaces and objects.