Cellulitis is a bacterial infection of the skin that is characterized by swelling, redness, warmth, and pain. The most common cause of cellulitis in adults with no other medical conditions is group A streptococcus, which is a bacterium commonly found in the throat and on the skin. Although cellulitis usually affects the legs, feet, and arms, the infection can also occur within the eye sockets, around the eyes, and on the toes. Treatment for cellulitis usually involves antibiotics and recurrence prevention.