COSMECEUTICALS DO NOT PRODUCE ACNE IF LABELED NONCOMEDOGENIC AND NONACNEGENIC

Similar to hypoallergenic, noncomedogenic and nonacnegenic are marketing claims carrying no implied regulation (Fig. 28.1). They were also developed to create a new consumer image for cosmetic lines designed to minimize acne. In order to make the claim noncomedogenic, rabbit ear or human comedogenicity testing should be undertaken. Both the animal and the human model are based on the presence of new comedone formation after the exposure of skin to the finished cosmetic. Human testing is considered to be more accurate, but the results are highly dependent on the skill of the contract testing laboratory. Acnegenic claims are based on human use testing and the evaluation of volunteer subjects following product use for an increase in the presence of acne. Many manufacturers, however, make noncomedogenic and nonacnegenic claims based on the safety profiles of the individual ingredients in the formulation. This is inaccurate. Noncomedogenic and nonacnegenic claims should be made based on clinical testing of the finished formulation. The dermatologist should still consider all products labeled noncomedogenic or nonacnegenic as problematic.

Fig. 28.1 Acne and comedone formation can occur even with products bearing the noncomedogenic and nonacnegenic label

MINERAL OIL IS COMEDOGENIC

Mineral oil is one of the most common ingredients in skin care products and colored cosmetics (Fig. 28.2). It is a lightweight inexpensive oil that is odorless and tasteless. One of the common concerns regarding the use of mineral oil is its presence on several lists of comedogenic substances. These comedogenic lists were developed many years ago, yet remain frequently quoted in the dermatologic literature. There are several important points to consider. First, there are different grades of mineral oil. There is industrial grade mineral oil, which is used as a machine lubricant, that is not of the purity required for skin application. Cosmetic grade mineral oil is the purest form without contaminants. Industrial grade mineral oil may be comedogenic, but cosmetic grade mineral oil is not. Quality manufacturers only purchase quality products from quality suppliers who guarantee the quality of the materials they provide. I believe that cosmetic grade mineral oil is noncomedogenic and I have never found it to be comedogenic in any of the testing I have performed for the skin care industry.

Fig. 28.2 Numerous dermatologist-recommended facial moisturizers contain mineral oil

SUNSCREENS PRODUCE ACNE

Many patients note the occurrence of ‘breakouts’ following the use of sunscreens. These patients typically present with perifollicular papules and pustules in a random distribution over the face. This eruption appears within 24–48 hours after wearing a facial sunscreen. I have not performed biopsies on patients who develop this problem, but I would like to put forth a hypothesis based on my knowledge of how sunscreens function.

Most of the sunscreens on the market today are based primarily on UVB-absorbing ingredients, such as octyl methoxycinnamate, oxybenzone, homosalate, etc. Many also have UVA-absorbing ingredients, such as avobenzone, titanium dioxide, or zinc oxide, as secondary sunscreens. All of the UVB sunscreens and avobenzone function by transforming ultraviolet radiation to heat energy through a process known as resonance delocalization. This heat energy is appreciated by many patients who will state that they do not like wearing sunscreens, since the gels or lotions make them feel hot. In some patients, I believe that the increased sweating induced by the sunscreens accompanied by the warm sunny weather cause increased activity by the eccrine glands. This may cause miliaria rubra that may be magnified by the occlusive nature of the water-resistant, rubproof product. Thus, I believe that much of the problem with sunscreen-induced breakout is the formation of papules or pustules around the eccrine duct ostia without the sebaceous gland involvement that characterizes true acne.

VITAMIN E CAPSULES IMPROVE THE APPEARANCE OF SCARS

A common practice among lay persons is to break open a vitamin E capsule and massage the oil over scars to improve their cosmetic appearance. I do not believe that this is a medically sound practice. The vitamin E present in vitamin capsules is intended for oral administration with subsequent absorption across the digestive mucosa. The vitamin E is dissolved in vegetable oil, which may be comedogenic. Furthermore, vitamin E administered in this fashion cannot be absorbed through the skin. The main benefit is the massaging action, which may be beneficial to the scar. I would recommend a moisturizer designed for skin application as a massage product rather than oral vitamin E capsules.

GLYCOLIC ACID APPLICATION CAN REDUCE PORE SIZE

Glycolic acid is a water-soluble chemical exfoliant. It cannot enter the oily milieu of the pore and thus does not exfoliate within the pore. Glycolic acid may improve the smoothness of the skin surface, creating the illusion of reduced pore size, but it cannot measurably reduce pore size. As a matter of fact, there is no cosmeceutical ingredient that can measurably reduce pore size.

Salicylic acid is an oil-soluble chemical exfoliant that can remove debris from the pore, creating the appearance of skin smoothness, but it too cannot measurably reduce pore size. It is important to distinguish between real pore size reduction and an improved cosmetic appearance. Figure 28.3 demonstrates the appearance of pores containing keratotic debris. Removal of this debris with a salicylic acid peel can improve the appearance of the pores and can shrink the size of dilated pores due to debris presence, but the physical size of the pore cannot be altered.

Fig. 28.3 The appearance of pores containing keratotic debris. Removal of this debris with a salicylic acid peel can improve the appearance of the pores and can shrink the size of dilated pores due to debris presence, but the physical size of the pore cannot be altered

TRETINOIN TOPICALLY AIDS IN THE TREATMENT OF ACNE SCARRING

Whether tretinoin aids in the treatment of acne scarring is rather controversial, even among dermatologists. Tretinoin normalizes follicular keratinization, which improves comedonal, pustular, and superficial papular acne. This effect may smooth out the skin around acne scars simply by treating the acne. Tretinoin also increases collagen production after extended use, which may improve acne scarring. The degree to which tretinoin improves pitted acne scarring has never been quantified and more research is needed in this area. However, it is unlikely that this research will be forthcoming from the pharmaceutical industry, since tretinoin is now generic and there is currently no indication for acne scarring, only acne treatment.

A COMPLEX SKIN CARE REGIMEN OF MULTIPLE CLEANSERS, MOISTURIZERS, AND ANCILLARY SKIN CARE PRODUCTS IS NECESSARY FOR CLEAR SKIN

There are many different approaches to skin care. There is the no nonsense bar of soap and water twice daily approach and the 20 step skin care routine approach. Which is better? I am not sure I know the answer. In Japan, skin care is a complex ritual of multiple cleansers, toners, and moisturizers. The Japanese also feel that they have the most sensitive skin of all races and the incidence of atopic dermatitis is dramatically rising in their country. Is this due to the use of extensive skin care products? I also do not know the answer to this question. However, there is no doubt that the more the skin is manipulated, the more opportunity there is for problems to arise. Perhaps the old adage of everything in moderation is the best advice, even when it comes to skin care (Fig. 28.4).

Fig. 28.4 There is no scientifically proven dermatologic benefit to the use of complex regimens for skin care

BREAKOUTS AFTER THE AGE OF 30 IN WOMEN ARE RARE AND WILL BENEFIT FROM SPECIAL SKIN CARE

Acne after age 30 is actually becoming more and more common in women. The cause of this trend is not totally known, but appears to be related to fluctuating hormones and the onset of the premenopause and the perimenopause. This supposition is based on the observation that the acne is not characterized by open and closed comedones, but rather inflammatory papules and pustules. Since these lesions are deep seated within the lower epidermis and dermis, it is not possible for special skin care routines to have a dramatic effect. Thus, the use of oral antibiotics and hormonal therapies, such as birth control pills or estrogen replacement therapy, are the best options for acne control. Cosmetics and skin care products have little effect.

COSMECEUTICALS CANNOT UNDERGO RELIABLE COMEDOGENICITY TESTING

Comedogenicity testing should be performed routinely on products designed for persons with acne. In the past, comedogenicity was assessed in the rabbit ear assay by applying the final formulation inside a rabbit ear and then visually assessing the presence or absence of comedones. This test was not felt to have much human validity and animal testing has fallen out of favor, thus the rabbit ear assay has given way to testing on human volunteers. Comedogenicity testing is now performed routinely by applying the final formulation to the upper back daily for 14 consecutive days in persons capable of forming comedones on the upper back. A positive control, in the form of tar, is applied and a negative control, in the form of pure petroleum jelly, is also used. The comedones are extracted from the upper back with cyanoacrylate glue placed on a microscope slide. Any increase in comedone formation following the 14-day exposure to the final cosmetic formulation is considered comedogenic. This human model has proven reproducible, but only in persons capable of forming upper back comedones. Thus, the accuracy of the human comedogenicity test depends on the accuracy of panelist selection.