What is a classic sign of a skin and soft tissue infection?

Pus presence is a classic sign of a skin and soft tissue infection because it indicates the presence of infection and inflammation. Pus forms as a result of the body’s immune response to pathogens, such as bacteria, entering the skin or underlying tissues. It is composed of dead white blood cells, bacteria, and tissue debris, making it a direct indicator of an active infection that the body is attempting to fight off.

In contrast, while dry skin, skin discoloration, and hardening of the skin can occur in various dermatological conditions, they are not as specific to infections. Dry skin can stem from environmental factors or skin conditions, skin discoloration might be due to various causes, including vascular issues or trauma, and hardening of the skin can indicate chronic conditions unrelated to acute infections. Therefore, the presence of pus is a more definitive and classic sign of a skin and soft tissue infection.