What is the primary cause of cellulitis?

Cellulitis is primarily caused by bacterial infection, making it essential to understand the role of bacteria in this condition. The most common pathogens responsible for cellulitis are Streptococcus and Staphylococcus species, particularly Staphylococcus aureus, including its methicillin-resistant strain (MRSA). These bacteria enter the skin through breaks or wounds, leading to an inflammatory response characterized by redness, warmth, swelling, and pain in the affected area.

While viruses, fungi, and parasites can lead to skin infections and other dermatological issues, they do not typically cause cellulitis. Viruses may cause rashes or other skin-related symptoms, fungi are more associated with conditions like ringworm or athlete's foot, and parasites can lead to infestations but are not recognized as primary culprits in the development of cellulitis. Understanding that bacteria are the leading cause of this condition is critical for accurate diagnosis and effective treatment.