Cellulitis is a bacterial skin infection causing redness, swelling, and pain, often in the lower legs. Tom Warren, MD, explains it results from bacteria entering compromised skin barriers like cuts or athlete’s foot but can sometimes occur without visible breaks. Diagnosis relies on clinical signs, and treatment typically includes oral or IV antibiotics, targeting common bacteria like streptococcus. Preventive measures include compression stockings, treating athlete’s foot, and maintaining good hygiene. Untreated cellulitis can spread, requiring urgent care if it worsens. Recovery is usually successful with timely intervention.