Why do cat scratches swell up? - briefly
Cat scratches often swell up due to bacteria, such as Bartonella henselae, entering the skin, triggering an immune response that causes inflammation and redness.
Why do cat scratches swell up? - in detail
When a cat scratches the skin, the body’s immune system immediately responds to the injury, often leading to swelling. Cat scratches can introduce bacteria, such as Bartonella henselae, which causes cat scratch disease, or other pathogens from the cat’s claws or surrounding environment. The skin’s natural barrier is compromised, allowing these microorganisms to enter the tissue. The immune system detects this invasion and triggers an inflammatory response to combat potential infection. This process involves the release of histamines, cytokines, and other signaling molecules that increase blood flow to the affected area, causing redness, warmth, and swelling. Additionally, white blood cells are recruited to the site to neutralize any pathogens, further contributing to the swelling. In some cases, the scratch may also damage small blood vessels, leading to minor bleeding or fluid accumulation in the tissue. If bacteria are present, the immune response can become more pronounced, potentially resulting in localized infection, pus formation, or even systemic symptoms like fever. Proper cleaning of the wound and monitoring for signs of infection are essential to prevent complications.