AcneNet This Month
July 2000

Tip of the Month

If you are being treated by a physician for acne, the question uppermost in your mind is: Am I getting improvement? Your doctor has the same question in mind, and you both want an answer that will best guide your future treatment.

Here are a few things you can do when you see your doctor, to help your doctor make a realistic assessment of your progress in treatment:

• Wear a hair style that leaves your forehead and hairline open and uncovered. Hair over the forehead can mask comedones and other acne lesions around the hairline—an area where they can be quite numerous. Hair styled over the forehead does not necessarily worsen acne, however, so an over-the-forehead style may be okay most of the time.

• If you are a male, shave on the morning of the examination. Beards and stubble can cover lesions, or mask the appearance of lesions, making them difficult to assess. Usually, a male with facial acne should not wear a beard during treatment.

• Do not wear cosmetics on the day of the examination. Cosmetics can disguise the appearance of lesions. If you try to remove cosmetics just prior to the examination, the skin redness resulting from washing and rubbing can make examination difficult.

• Don’t try to be helpful by stretching your forehead or facial skin, unless you asked to do so by the doctor. Stretching the skin can change the appearance of lesions, and substantially alter the appearance of "sandpaper acne" on the forehead.

• Ultraviolet radiation from sunlight or tanning lamps can change the color of the skin. This may camouflage noninflamed lesions, and make inflamed lesions look less inflamed. If you are in a treatment program, it is best to ask your doctor about tanning.

Fact of the Month

Propionibacterium acnes is a bacterium that doesn’t like to come into contact with air. Yet, it thrives on areas of the body most exposed to air—the face and the nose. How it manages to do this is an interesting example of bacterial survival strategy.

P. acnes is often identified as a contributing cause of some cases of acne. But, P. acnes is also a normal resident in the skin and nose, and its involvement in acne can be viewed as an encounter between bacterial survival strategy and human physiology.

Here is the explanation:

P. acnes belongs to the large group of bacteria that are called anaerobes—literally, "air haters". In the human body, anaerobes are typically found in the intestines and in tissues that normally do not come into contact with air. Many anaerobes have found air-tight environmental niches where they live comfortably and cause no harm. They may even be useful by repelling invasions by harmful bacteria. Some anaerobes are "bad actors" that may cause serious disease—for example, the anaerobe that infects injured tissue and causes gas gangrene.

One way that P. acnes solved the problem of being an anaerobe in an air-exposed environment was by learning to live in the microhabitat of sebaceous follicles. The sebaceous follicle is a microhabitat that is a sealed chamber. The contents of the sebaceous follicle include the hair that grows from the "root" at the base of the follicle, dead cells and parts of cells, and the oily sebum on which P. acnes feeds. The hair, the dead cells and the sebum effectively seal the follicle’s opening, creating an ideal environment for anaerobic P. acnes. Within the sebaceous follicle the mixture of sebum and shed cells facilitates overgrowth of P. acnes.

Propionibacterium acnes is found in its greatest numbers in skin with a high sebum content: forehead, sides of the nose and scalp. While P. acnes lives comfortably in this environment, some of the chemicals it produces as a byproduct of ingested sebum can contribute to the inflammation of acne.

Regular, gentle cleansing can help reduce the amount of sebum on oily skin (click on Acne treatments for more information). While this may not reduce the P. acnes population, it may promote better cosmetic appearance. Antibiotics and antibacterials can reduce the P. acnes population. A topical antibacterial such as benzoyl peroxide, used daily as directed, can reduce P. acnes concentrations by 90 percent or more.

Topical antibiotics, and antibiotics taken as pills (systemic antibiotics), decrease P. acnes concentrations in sebaceous follicles, but this should be done only after evaluation by a dermatologist determines that the use of antibiotics is likely to be effective.

Question of the Month

Each month we pose a question that is answered the following month. This month’s question:

My doctor insists that acne is not an infectious disease, but he wants to treat me with antibiotics because he thinks Propionibacterium acnes is contributing to the severity of my acne. If acne isn’t an infectious disease, why do I have to take antibiotics?

We’ll have the answer, and a discussion of the answer, on AcneNet next month.

Answer to last month’s Question of the Month

Last month’s question was:

I have friends with acne, and some of them have mostly blackheads and whiteheads and oily skin. I have acne, but my acne lesions usually get inflamed. Why is my acne so different?

Answer: Inflammation is a normal stage in the evolution of an acne lesion.

A person with acne should not feel "different" because acne lesions become inflamed. Inflammation is a part of the process by which acne lesions resolve. However, severe inflammation can contribute to scarring and should be treated.

The evolution of an acne lesion is a dynamic process. Most lesions do not resolve directly, but pass through several stages before finally disappearing. A very few can appear and disappear within a day.

It is usually not possible to predict how long an acne lesion will last when it first appears. Each person with acne may have a general idea how long a lesion will last, based upon his or her own experience with acne. However, there is no set pattern of evolution that is characteristic for comedones, papules, pustules, nodules and cysts.

Acne inflammation includes both irritant and immunologic processes.

A primary irritant is free fatty acids. When a sebaceous follicle becomes plugged with sebum and dead skin cells, bacteria in the follicle may begin to multiply. One of the most common bacteria living in the follicle is Propionibacterium acnes, which "eats" sebum and releases free fatty acids as a by-product. As P. acnes multiples, more free fatty acids will be produced, and the acne lesion becomes more irritated and inflamed. Other chemical substances produced by P. acnes also may contribute to inflammation.

The other major cause of inflammation is the body’s response to the developing acne lesion. This is an immunologic response, which brings white blood cells into the follicle and surrounding tissue to repair injury and fight bacteria. White blood cells are a first line of defense against injury and infection. Some white blood cells ingest bacteria and cellular debris. Others produce a host of antibodies and other substances that kill bacteria and help to repair damaged tissue. Some of these substances cause tissue to become inflamed as they do their jobs.

A typical course for a mildly inflamed acne lesion would be five to 10 days from formation to resolution. However, the lesion may resolve into a macule, a "red spot" that could persist for several weeks as damaged tissue continues to repair.

Some acne lesions follow a course from comedo to papule to pustule before resolving.

Acne lesions that develop into nodules or cysts may have a lifetime of weeks to months. These severely inflamed lesions are most likely to produce visible scars; they should be treated by a dermatologist.