April 2001

Tip of the Month

When you read about acne or other skin diseases, you encounter words or phrases that may be confusing. For example, the words used to describe the lesions of acne—comedo, papule, pustule, nodule and cyst—are understandable only if you know each word’s definition. It also is helpful to have a photo that is characteristic for each type of lesion.

Here is a brief summary of definitions of words used to describe acne, with accompanying photos. Let’s begin, though, with the definition of lesion, an all-purpose word:

Lesion—a physical change in body tissue caused by disease or injury. A lesion may be external (e.g., acne, skin cancer, psoriatic plaque, knife cut), or internal (e.g., lung cancer, atherosclerosis in a blood vessel, cirrhosis of the liver).

Thus, when you read about acne lesions you understand what is meant—a physical change in the skin caused by a disease process in the sebaceous follicle (Click on Why and how acne happens).

Acne lesions range in severity from comedones (blackheads and whiteheads) to nodules and cysts. Here is a brief definition of acne lesions:

Comedo (plural comedones)—A comedo is a sebaceous follicle plugged with sebum, dead cells from inside the sebaceous follicle, tiny hairs, and sometimes bacteria. When a comedo is open, it is commonly called a blackhead because the surface of the plug in the follicle has a blackish appearance. A closed comedo is commonly called a whitehead; its appearance is that of a skin-colored or slightly inflamed "bump" in the skin. The whitehead differs in color from the blackhead because the opening of the plugged sebaceous follicle to the skin’s surface is closed or very narrow, in contrast to the distended follicular opening of the blackhead. Neither blackheads nor whiteheads should be squeezed or picked open, unless extracted by a dermatologist under sterile conditions. Tissue injured by squeezing or picking can become infected by staphylococci, streptococci and other skin bacteria. The following photos are characteristic of acne with comedones:

(Photos used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides and the Sulzberger Institute for Dermatologic Education)

 

Papule—A papule is defined as a small (5 millimeters or less), solid lesion slightly elevated above the surface of the skin. A group of very small papules and microcomedones may be almost invisible but have a "sandpaper" feel to the touch. A papule is caused by localized cellular reaction to the process of acne. This photo shows papules and comedones on the face of an acne patient:

(Photos used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides and the Sulzberger Institute for Dermatologic Education)

Pustule—A dome-shaped, fragile lesion containing pus that typically consists of a mixture of white blood cells, dead skin cells, and bacteria. A pustule that forms over a sebaceous follicle usually has a hair in the center. Acne pustules that heal without progressing to cystic form usually leave no scars. This photo shows pustules, papules and comedones on the face of an acne patient:

(Photos used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides and the Sulzberger Institute for Dermatologic Education)

Macule—A macule is the temporary red spot left by a healed acne lesion. It is flat, usually red or red-pink, with a well defined border. A macule may persist for days to weeks before disappearing. When a number of macules are present at one time they can contribute to the "inflamed face" appearance of acne. This photo shows the "red face" appearance of acne with macules:

(Photos used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides and the Sulzberger Institute for Dermatologic Education)

Nodule—Like a papule, a nodule is a solid, dome-shaped or irregularly-shaped lesion. Unlike a papule, a nodule is characterized by inflammation, extends into deeper layers of the skin and may cause tissue destruction that results in scarring. A nodule may be very painful. Nodular acne is a severe form of acne that may not respond to therapies other than isotretinoin (Click on Acne treatment)

Cyst—A cyst is a sac-like lesion containing liquid or semi-liquid material consisting of white blood cells, dead cells, and bacteria. It is larger than a pustule, may be severely inflamed, extends into deeper layers of the skin, may be very painful, and can result in scarring. Cysts and nodules often occur together in a severe form of acne called nodulocystic. Systemic therapy with isotretinoin is sometimes the only effective treatment for nodulocystic acne. Some acne investigators believe that true cysts rarely occur in acne, and that (1) the lesions called cysts are usually severely inflamed nodules, and (2) the term nodulocystic should be abandoned. Regardless of terminology, this is a severe form of acne that is often resistant to treatment and likely to leave scars after healing. These photos show nodular, cystic acne:

(Photos used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides and the Sulzberger Institute for Dermatologic Education)

This month, Fact of the Month begins a three-part series updating information about Acne treatment. While the mainstays of acne treatment have remained the same for a number of years, new studies update information about standard therapies and some new therapies have become available.

The three-part series begins this month with over-the-counter topical medications and a discussion of comedo extraction. Topical Prescription Therapies will be discussed next month, followed by Systemic Therapies to complete the series.

Soap and water. Gentle cleansing of the skin with soap and water, no more than two or three times a day, removes excess oils (sebum) and may alleviate the "oily skin" appearance often associated with acne. There is no evidence that cleansing with soap and water prevents or clears up acne. Hard scrubbing, excessive cleansing (more than three times a day), or the use of harsh soaps or detergents may injure the skin and cause other skin problems in addition to acne.

Benzoyl peroxide. A mainstay of over-the-counter acne treatment, and a medication commonly prescribed by physicians to treat mild forms of acne. Benzoyl peroxide has been used in acne treatment for several decades; it was the first agent to be proven effective in the treatment of mild acne. The anti-acne effects of benzoyl peroxide are believed to be anti-bacterial with an accompanying decrease in some constituents of sebum. Benzoyl peroxide is available over-the-counter in a lotion or a gel. Its principal side effect is to cause excessive dryness of the skin. Benzoyl peroxide can bleach hair and fabric, including sheets, towels and clothing, so care should be taken when applying it. An old shirt should be worn when benzoyl peroxide is applied to the back or chest overnight.

Salicylic acid. This agent also is found in both over-the-counter and prescribed topical acne medications. Its anti-acne activity is believed to be in clearing dead cellular material that can plug sebaceous follicles. It may be combined with other agents such as sulfur in over-the-counter medications.

Sulfur. An acne treatment in use for 50 years or longer. In combination with other agents—e.g., alcohol, salicylic acid, and resorcinol—sulfur is still a constituent of some of the most heavily marketed over-the-counter medications. Sulfur is less frequently used by itself as an acne treatment due to its unpleasant odor. Although long used in treatment of acne, it is not known how sulfur acts on the skin to influence the development of acne.

Sulfurated lime. An older medication for treatment of various skin diseases and scabies. Sulfurated lime probably characterizes the medications that were the best available in past decades.

Resorcinol. Together with sulfur, a constituent of popular over-the-counter acne medications. Resorcinol is less frequently used alone in treatment of acne.

Alcohol and acetone. Acetone is a "degreasing" agent, and alcohol has a mild anti-bacterial activity. The two agents have been sometimes combined in over-the-counter medication. However, when acetone is used alone, it may have no effect in the treatment of acne.

Herbal, organic and "natural" medications. Over-the-counter products called "herbal," "organic" or "natural" are marketed as acne treatments but their effectiveness has rarely been tested in clinical trials. The value of such treatments is generally unknown.

Comedo extraction. Extraction of comedones should be performed only by a dermatologist, under sterile conditions, and usually only when comedones have not responded to other treatment. Acne patients should not attempt to extract comedones by squeezing or picking.

Ultraviolet light therapy. Ultraviolet light has not been proven effective as an acne treatment. At most, skin tanning may mask acne. However, skin tanning increases risk for other, more serious skin conditions such as melanoma and other skin cancers.

Light Chemical Peels. Glycolic acid and other chemical agents are applied by a dermatologist to loosen blackheads and decrease acne papules.

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

My friend wants to loan her blackhead extractor to me so I can remove my blackheads like she does. She bought her extractor by mail order, and she says she uses it every time a new blackhead appears. I have so many blackheads that I am tempted to accept her offer. Is using a blackhead extractor a good idea?

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:

My doctor is prescribing a topical retinoid for my acne. He said a retinoid is a substance related to vitamin A. If the drug is related to vitamin A, shouldn’t vitamin A dietary supplements be helpful in getting rid of acne?

Dietary vitamin A has multiple health effects in the human body. Vitamin A is essential for good vision. Extreme vitamin A deficiency can result in blindness, usually accompanied by dry, scaly skin. Vitamin A overdose that far exceeds the Recommended Dietary Allowance (RDA) of 5,000 IU can have effects nearly as catastrophic. Extreme vitamin A overdose can cause the skin to blister and peel—an effect first seen in early North Pole explorers who nearly died after eating polar bear liver that has an extraordinarily high vitamin A content.

Topical retinoids are usually prescribed as a treatment for moderate to severe acne. Side effects are chiefly dermatologic, including redness, scaling and dryness of the skin, itching and burning. These side effects can usually be managed by adjustment of the amount and timing of retinoid applied to the skin. Dose adjustment must be discussed with the dermatologist who prescribed the treatment.