Acne: Everything You Need to Know: By Vanessa Ng and David Robles, MD, PhD

Who gets Acne? 

Acne is a common skin condition involving blockage and inflammation of hair follicles.  About 50 million people in the United States have acne.  Acne affects 85% of all adolescents but it can also occur in adulthood.  Acne can develop on the face, neck, chest, shoulders, back and buttocks. 

Why do we get acne? 

Acne can be summarized as an interplay of the following four factors: (1) plugging of the follicle, (2) excess sebum production, (3) the presence and activity of bacteria, Propionibacterium acnes, and (4) inflammation. 

In order to keep the skin well lubricated, the body depends on sebaceous glands.  Sebaceous glands or oil glands are connected to hair follicles and secrete an oily substance called sebum.  Sebum is a mixture of triglycerides, proteins, cholesterol, and inorganic salts.  After sebum is secreted from the sebaceous glands, it travels up hair follicles and out through the pores of the skin.  This oily substance coats the surface of hairs and maintains them from drying.  Sebum also prevents excessive evaporation of water from the skin keeping the skin soft and inhibits the growth of certain bacteria. 

Although sebum normally plays a positive role in keeping skin healthy, there are exceptions. If the body produces excess sebum and dead skin cells, clogging of the pores may occur resulting in skin blemishes.  

Hormones and Bacteria

Acne is common in the teen years because during puberty, the sebaceous glands are stimulated by sex hormones.  Although sebum has bacteria-killing properties, under some conditions, bacteria may invade sebaceous glands. When bacteria gets into sebaceous glands or follicles this can produce folliculitis, which is a local inflammation.  Sebaceous glands contain ducts and if they are blocked, an abscess called a furuncle develops.  Most people who have acne also contain larger than average sebaceous glands.  When the ducts become blocked, their oily secretions accumulate and the bacteria Propionibacterium acnes may colonize the area resulting in inflammation. 

We shined a UV light in the dark on this boy with acne. What you see is orange-red fluorescence restricted to the follicles. The bacteria responsible for this is Propionibacterium acnes. P. acnes contributes significantly to the development of acne. These Gram-positive rods are found deep within the hair follicles. They naturally produce porphyrins (primarily coproporphyrin III) that fluoresce with UV light illumination. These bacteria release enzymes that contribute to the rupture of the pimple, and stimulate an inflammatory response that causes redness. 

Signs and Symptoms of Acne

Blemishes that are visible on the skin include closed comedos, which are whiteheads, and open comedos, which are blackheads.  Symptoms of acne may include pain, tenderness, or erythema.

How is Acne Treated?

Treatments for acne include topical and oral antibiotics.  Other alternatives include vitamin A derivatives such as tretinoin and isotretinoin.  Topical antibiotics work by killing excess skin bacteria and are applied directly onto the skin by gel or cream form.  For acne that is moderate to severe, oral antibiotics may be prescribed to eliminate bacteria and reduce inflammation. Tretinoin is an FDA approved retinoid that works by removing dead skin cells and prevent and clogging of the pores. 

What is "Accutane" aka Isotretinoin?

In the most severe cases of acne, isotretinoin (most people know it as “Accutane") may be prescribed.  Isotretinoin is a compound that is structurally similar to vitamin A.  Isotretinoin reduces oil gland activity, and therefore decreasing sebum production.  By reducing the activity of the sebaceous gland, it limits the amount of bacteria in the follicle. There have been reports of side effects while using isotretinoin including dry skin and eyes, chapped lips, and depression. Research has also found that using isotretinoin during the first month of pregnancy may induce birth defects (teratogenic).  Previous controversial associations with inflammatory bowel diseases and mood disorders, like depression, have essentially been disproved by new studies. 

A patient with severe nodular and cystic acne successfully treated with Isotretinoin.

Follow David Robles, MD, PhD