What is acne?
Acne is a common skin condition. It is caused by inflammation of the hair follicles and oil-producing (sebaceous) glands of the skin.
Hair follicles are the tiny structures that grow hair in the scalp. Sebaceous glands produce sebum. On areas where acne develops, sebaceous glands surround the hair follicles. The combination of the sebaceous glands and the hair follicles is the "pilosebaceous unit," where acne pimples and cysts develop. Sebum moisturizes hair and skin. Each hair pushes up through the skin surface along with sebum.
To continue reading this article, you must log in.
Subscribe to Harvard Health Online for immediate access to health news and information from Harvard Medical School.
- Research health conditions
- Check your symptoms
- Prepare for a doctor's visit or test
- Find the best treatments and procedures for you
- Explore options for better nutrition and exercise
I'd like to receive access to Harvard Health Online for only $4.99 a month.Sign Me Up
Already a member? Login ».
As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Please note the date of last review or update on all articles.
No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.