A 2009 study showed that an unmedicated ZnO/petrolatum paste was effective in restoring the properties of the skin, allowing for balanced transepidermal water loss and water retention by SC previously compromised by diaper dermatitis. This skin condition affects approximately 50% of infants and a small percentage of the bedridden elderly (Int. J. Cosmet. Sci. 2009;31:369-74).
In 2010, a study that assessed the effectiveness of topical ZnO ointment using the rabbit ear hypertrophic scar model showed that the application of 40% ZnO significantly reduced clinical scar hypertrophy scores at 6 weeks compared with placebo. The researchers concluded that these results may suggest clinical applications for ZnO in the treatment of hypertrophic scars in humans (Burns 2010;36:1027-35). In addition, ZnO has demonstrated antibacterial properties, with nanoparticles exhibiting more potent antibacterial activity than bulk ZnO (Sci. Technol. Adv. Mater. 2008;9:1-7).
Products
ZnO is a key ingredient in calamine lotion, an antipruritic compound used to treat various mild conditions such as bites and stings from insects, eczema, poison ivy, rashes, and sunburn. It is also available over the counter in ointment or suppository form for healing hemorrhoids and fissures. In addition, ZnO is used widely in baby powders, barrier creams, moisturizers, antiseptic ointments, antidandruff shampoos, athletic bandage tape, and, of course, sunscreens.
Conclusion
ZnO is a versatile inorganic metal oxide with multiple indications in dermatology. Consequently, it is included in a wide array of skin care products, including shampoos, moisturizers, and sunscreens. Its use in nanoparticle form, along with the similar use of its physical sunscreen counterpart TiO2, represents one of the many subjects debated within the larger context of sunscreen use. The next edition of this column will focus on the relative safety of zinc oxide nanoparticles.
Dr. Baumann is chief executive officer of the Baumann Cosmetic & Research Institute in Miami Beach. She founded the cosmetic dermatology center at the University of Miami in 1997. Dr. Baumann wrote the textbook "Cosmetic Dermatology: Principles and Practice" (McGraw-Hill, April 2002), and a book for consumers, "The Skin Type Solution" (Bantam, 2006). She has contributed to the Cosmeceutical Critique column in Skin & Allergy News since January 2001 and joined the editorial advisory board in 2004. Dr. Baumann has received funding for clinical grants from Allergan, Aveeno, Avon Products, Galderma, Mary Kay, Medicis Pharmaceuticals, Neutrogena, Philosophy, Stiefel, Topix Pharmaceuticals, and Unilever.
This column, "Cosmeceutical Critique," appears regularly in Skin & Allergy News, a publication of Frontline Medical News.