The Sequence of an Acne Lesion

• A keratinized plug blocks sebum from wicking out along the hair shaft.
• Stagnant sebum is broken down by bacterial enzymes into a short-chained fatty acid.
• Irritation in the form of a papule is formed.
• Increased blood flow activates the immune system.
• White blood cells are rushed in to deal with the foreign matter.
• Pustules are formed.