Cosmeceutical Critique: FragranceDr. Leslie Baumann
Volume 33, Issue 7, Page 44 (July 2002)
Fragrance is a critical component in cosmeceutical products and has become even more so with the growing popularity of aromatherapy. Our patients enjoy the olfactory sensations that they experience when using these products. However, the very ingredients that contribute to these wonderful scents can be irritating to the skin.
To learn more about the use of fragrance in cosmeceuticals and topical medications, I spoke with Yohini Appa, Ph.D., executive director of scientific affairs at Neutrogena Corp. in Los Angeles.
Dr. Baumann: What does “fragrance free” mean?
Dr. Appa: Because there is no legal definition of the term “fragrance free,” it can be a source of confusion. The U.S. Code of Federal Regulations defines the term fragrance as “any natural or synthetic substance(s) used solely to impart an odor to a cosmetic product.” Fragrances used in cosmetic products are usually compounded from hundreds of individual fragrance ingredients.
The most common interpretation of “fragrance free” is that the product contains neither compounded fragrances nor ingredients added solely to impart an odor to the product. Some products labeled as fragrance free may contain single ingredients that are included to perform some function other than providing an odor.
When a product is labeled “unscented,” it may contain fragrance ingredients that serve to mask any offensive odor originating from the raw materials used. However, these fragrance ingredients are present in a smaller amount than is needed to impart a noticeable scent.
Dr. Baumann: How is the safety of added fragrances tested?
Dr. Appa: There are several steps in reviewing/establishing the safety of fragrances. First, the ingredients of a fragrance are reviewed and compared with industry-developed restricted lists, such as internal corporate guidelines or guidelines from the International Fragrance Research Association (IFRA). IFRA is a self-regulatory body of the fragrance industry charged with ensuring the safety-in-use of fragrance material. IFRA maintains an Industry Code of Practice on specific fragrance materials, limiting or prohibiting their uses in response to adverse reactions.
IFRA categorizes the controlled fragrance materials as potential sensitizers, dermotoxic agents, or photoallergens. The list further indicates whether the fragrance materials are prohibited, have restricted use, or are on the restricted list because of a lack of adequate data. This list is updated periodically as new scientific data relating to fragrances are obtained.
Here at Neutrogena, the fragrance's proprietary ingredient disclosure is reviewed by a dermatologist/toxicologist with contact dermatitis expertise. Individual fragrance ingredient levels are compared with contact dermatitis literature with regard to reaction thresholds.
This is important, because the complexity of fragrance bouquets makes it difficult to eliminate all traces of fragrances that are identified as potential allergens. Certain components may be allowable on the basis of known reactivity thresholds and product category. If a fragrance formula passes these screenings, it is then evaluated by patch test at exaggerated levels to determine its potential to elicit allergic contact dermatitis.
After a 2-week rest period, challenge patches are applied to the original test site and to a naive test site on the patient's back. Test sites are graded at 48 and 96 hours after application. Next, the finished product with fragrance incorporated is evaluated for safety in a controlled-use study of 40-50 subjects from the target consumer population. Subjects use the product according to label directions for 4 weeks under the supervision of a trained clinician and are evaluated for objective signs of skin irritation (erythema, edema, or dryness) as well as subjective signs (burning, stinging, itching, tightness, or tingling).
When we wish to ensure tolerance by individuals who are prone to dermatitis, we also conduct testing on individuals who have been diagnosed as fragrance sensitive.
Dr. Baumann: Which fragrances are the most common sensitizers and should be avoided by patients with sensitive skin?
Dr. Appa: The eight most common fragrance allergens are cinnamic alcohol, cinnamic aldehyde, eugenol, –amylcinnamic aldehyde, hydroxycitronellal, geraniol, isoeugenol, and oak moss absolute. They are available to dermatologists to patch test as “fragrance mix.” Fragrance mix is an excellent screening tool and identifies approximately 70%-90% of patients with fragrance allergy. Recently in Europe, the Scientific Committee on Cosmetic Products and Nonfood Products has identified 26 ingredients that have allergenic potential.
The European Commission has proposed requiring that these allergens be listed in the product package's ingredient declaration with a warning statement: “Can cause allergic reaction.”
Dr. Baumann: Is fragrance allergy common?
Dr. Appa: Fragrance allergy is reported to affect approximately 1% of the general population. However, when patients are patch tested in contact dermatitis clinics, 6%-11% respond positively, with a relevance of 50%-65%.
Dr. Baumann: When patients have a positive patch test, they then have an idea of which ingredients to avoid in cosmeceutical products. A new resource can help dermatologists steer their patients clear of known allergens. The Contact Allergen Replacement Database soon will be available to members of the American Contact Dermatitis Society. For more information, see www.contactderm.org.
DR. LESLIE S. BAUMANN is director of cosmetic dermatology at the University of Miami. To respond to this column, or to suggest topics for future columns, write to Dr. Baumann at our editorial offices or via e-mail at firstname.lastname@example.org.
© 2002 International Medical News Group. Published by Elsevier Inc. All rights reserved.