What are inflammatory acne lesions?

Dr. Doris Day, MD
All acne lesions start as a microcomedo. This consists of a microscopic plug of the follicle. The different types of acne lesions that evolve from the microcomedo are named based on what they look like and whether there are active Propionibacterium acnes (P. acnes) at work causing a localized infection. Inflammatory lesions contains active P. acnes within the follicle and include:
  • Papules: These are inflamed (red, swollen) lesions that usually appear as small, pink bumps on the skin and can be itchy or tender to the touch.
  • Pustules: These are papules that are topped with pus-filled lesions that may be red at the base. The pus consists of dead white blood cells and bacteria that are a result of a war between the white blood cells and the P. acnes in the follicle that then overflowed to the surface of the skin. 
  • Nodules: These are large, painful, solid, or fluctuant lesions that are lodged deep within the skin with a small opening to the surface where the follicle exits to the skin. They often feel hard to the touch because they consist of a combination of oils and proteins that have accumulated within the nodular cavity. They can last for months and leave behind crater-like scars.
  • Cysts: These are rarely found in acne, and the term is generally abandoned in favor of nodulocystic or severe nodular acne. This consists of multiple deep, painful, pus-filled lesions that can leave behind crater-like scarring in the skin.
100 Questions & Answers About Acne

More About this Book

100 Questions & Answers About Acne

100 Questions and Answers About Acne provides you with all the information you need to manage your complexion problems. Written by Dr. Doris J. Day, a world-class expert in the field, this clearly...

Continue Learning about Acne

Avoiding Adult Acne
Avoiding Adult Acne
Won't they ever go away? As an adult, you expect pimples to be a thing of the past. But for many adults, blemishes continue to mar otherwise healthy s...
Read More
Why am I now getting acne as an adult?
Dr. Mehmet Oz, MDDr. Mehmet Oz, MD
Rather than occurring in the teen years, and fading in the 20s, adult onset acne begins for peop...
More Answers
6 Weird Facts About Acne
6 Weird Facts About Acne6 Weird Facts About Acne6 Weird Facts About Acne6 Weird Facts About Acne
Discover bizarre truths about acne and learn how to fight a bad breakout.
Start Slideshow
How Do I Treat Blackheads?
How Do I Treat Blackheads?

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.