Redness

Redness (or edema) is caused when the body responds to an infection.  When the body fights infection, inflammation ensues and redness is the manifestation of the infection and inflammation. 

Redness can be a short term or long term consequence of acne.  Acne inflammation and redness may last only as long as the inflammation and infection persists.  But redness related to scabs or scarring can last much longer.  As a scar heals blood is drawn to the area as part of the natural healing process.  This in turn leads to prolonged redness in areas where scabbing and scarring have occurred. 

Another cause of redness that is commonly mistaken for acne is Acne Rosacea.  Acne Rosacea is listed as one of the acne imposters, and although acne is present in Acne Rosacea, the primary cause of redness with theis condition is the Rosacea itself.