Trends in the use of topical over the counter products in the management of dermatologic disease in the United States
- Author(s): Nolan, Bridgit V
- Levender, Michelle M
- Davis, Scott A
- Feneran, Ashley N
- Jr, Alan B Fleischer
- Feldman, Steven R
- et al.
Published Web Locationhttps://doi.org/10.5070/D33pk0x5zv
Trends in the use of topical over the counter products in the management of dermatologic disease in the United StatesCenter for Dermatology Research, Departments of Dermatology1, Pathology2, and Public Health Sciences3, Wake Forest University School of Medicine, Winston-Salem, North Carolina
Bridgit V Nolan1 MD, Michelle M Levender1 MD, Scott A Davis1 MA, Ashley N Feneran1 BS, Alan B Fleischer Jr1 MD, Steven R Feldman1,2,3 MD PhD
Dermatology Online Journal 18 (2): 1
BACKGROUND: Over the counter (OTC) products play an important role in treating and preventing disease in the U.S. Topical OTCs are widely used but use in dermatology is not well defined. OBJECTIVE: To characterize topical OTC use in the U.S. Methods: The National Ambulatory Medical Care Survey was queried for physician visits in which topical OTCs were recorded. Physician specialty, patient demographics, and diagnoses were examined and linear regressions were performed to determine trends over time. RESULTS: From 1989 to 2008, there were an estimated 320 million visits documenting topical OTC recommendations; the majority of which were visits to a dermatologist (33.5%). Dermatologists most commonly recommended hydrocortisone (16.9%), benzoyl peroxide (13.3%), and sunscreen (7.4%). Dermatologists were more likely than other providers to use moisturizers in the treatment of dermatologic disease. Overall, topical OTC recommendations by all physicians has decreased over time (p<0.0001). However, dermatologists’ recommendations for moisturizers and sunscreens has increased significantly. CONCLUSION: Topical OTC products have an important role in the prevention and treatment of dermatologic disease. Topical OTC recommendations are decreasing over time whereas their use as complementary components (sunscreen/moisturizers) appears to be increasing. Increased awareness of the utility of these agents may help to improve patient outcomes.
Over-the-counter (OTC) products play an integral role in the treatment and prevention of many common conditions. Currently, there are over 100,000 OTC products on the market in the United States (U.S.), which contain over 1,000 distinct active ingredients and span more than 80 therapeutic categories [1, 2]. OTCs are an accepted treatment for many common medical problems, including musculoskeletal pain, headaches, cold symptoms, allergies, heartburn, and dermatitis. They are fundamental in preventive health. Various agents aid in the prevention of dental caries and sunburn, promote heart health, in the case of aspirin and fish oil capsules, and are integral to smoking cessation programs. OTC products are included in many professional medical associations’ treatment guidelines for a variety of conditions in the U.S. and are widely used by consumers [3, 4].
In a recent survey of 2,590 American adults, the 4 most commonly used medications in the U.S. — acetaminophen, ibuprofen, aspirin, and pseudoephedrine hydrochloride — are all available OTC . A survey conducted by the National Council on Patient Information and Education revealed that 59 percent of adults (n=1,011) had taken an OTC medication in the past 6 months, which was slightly higher than prescription medication use (54%) . Among those who reported using an OTC, 10 percent reported that it was for skin problems and 12 percent for infections including athlete foot or yeast infection .
Dermatologic conditions are among the most common medical problems in the U.S., with one-third of the population experiencing at least one active skin disease at any given time . Between 7 and 10 percent of all visits, regardless of specialty, are for skin disease treatment . Dermatologic conditions frequently require topical therapies, of which OTC options abound. Total expenditures for topical OTCs in 2004 were estimated at $2.6 billion, which represents approximately 9 percent of total direct costs associated with dermatologic disease. Estimated retail sales of OTC acne products were $333 million in 2009, which had increased from $318 million in 2006. Even more staggering were the retail sales of sunscreens, estimated at $499 million in 2009, also increased from $366 in 2006 .
We sought to better characterize use of topical OTC products in the U.S. from 1989 to 2008 with a focus on dermatologic conditions.
The National Center for Health Statistics (NCHS) conducts the annual National Ambulatory Medical Care Survey (NAMCS) as an ongoing survey to provide descriptive data regarding the utilization of ambulatory medical care services in the U.S. Sampling is limited to non-federally employed physicians primarily involved in providing outpatient medical services in the U.S. The multistage probability sampling design is stratified by primary sampling unit (county, contiguous counties, or standard metropolitan statistical area), then by physician practices within the sampling unit, and finally, by patient visits within the 52 weekly randomized periods. Participating physicians are randomly assigned to a one week reporting period during which time a systematic random sample of visits are recorded. For small practices, a 100 percent sample of visits during the one week period may be possible. For larger practices, 20 percent of patient visits are randomly sampled. Data related to patients’ demographic characteristics and presenting symptoms, diagnostic procedures, services provided, physicians’ diagnoses, patient management, and medications ordered are obtained. Subsequent to data collection, sampling weights are applied to the data to generate nonbiased national estimates of outpatient medical services in the U.S.
In the present study, the NAMCS database was queried to identify all visits to all specialties between 1989 and 2008 in which topical OTCs were recorded. When a medication or OTC product is recorded for a patient visit in the NAMCS database, it indicates that medication or product was either currently being used by the patient, was dispensed in the office, or was prescribed or recommended by the physician at the time of that visit. For the purposes of this study, all medications and products found in the NAMCS database from 1989 to 2008 were reviewed to manually create a list of products that would be defined as topical OTCs. We defined topical OTC products as topical agents that can be obtained without a prescription and are designed to treat dermatologic conditions involving the skin and/or the oral, vaginal, and anal mucosa (Appendix 1). Oral, injectable, and intravenous medications were excluded. For products available in both prescription and OTC forms, all products were included as OTC; such ambiguities were encountered relatively infrequently. OTC products bearing different brand names but sharing the same active ingredient were combined and analyzed as a group (Appendix 2). Resulting visits were analyzed for frequency of topical OTC use by physician specialty, by diagnosis, and by patient age, gender, race, and payer type.
Topical OTC use was also analyzed by therapeutic category. The NAMCS database follows the Multum classification scheme to assign drug categories. All products were reviewed and classified based on primary indication into the following categories: hydrocortisone (HC) preparations, moisturizers, anti-infectives, antiseptics/disinfectants, acne products, antipruritics/analgesics, cleansers/soaps, shampoos/conditioners, sunscreens, keratolytics, and miscellaneous (Appendix 3). Because of changes in the NAMCS coding during the study interval, it was necessary to combine non-white, non-black races (Asian, Native Hawaiian/Other Pac Islander, and American American/Alaska Native) into one “other” category and to analyze this group as a single entity. Additionally, trends in topical OTC use over time were analyzed by linear regression. All data analysis was performed using Statistical Analysis System (SAS®) software (SAS Institute Inc, Cary, NC).
Topical OTC products were used in approximately 320 million visits to U.S. physicians from 1989 to 2008. The top 3 specialties associated with topical OTC use were dermatologists (33.5% of total OTC use), general/family medicine (19.7%), and pediatrics (18.9%) (Table 1). Topical OTC use did not vary by gender or race (Table 2). Patients aged 0-9 were more likely than all other age groups to use topical OTCs, which were recorded in nearly a quarter of their visits (23.4%); OTC use among all other age groups did not vary (Table 2). Analysis by payer type revealed that topical OTCs were more likely to be used in visits coded as “no charge” and “worker’s compensation” than all other payer types (Table 2).
Among therapeutic categories, anti-infective products (19.6%) were most commonly used, followed by HC preparations (16.9%), acne products (14.5%), and moisturizers (12.2%) (Table 3). Analysis of individual OTC product use among dermatologists revealed that HC (16.9%) and benzoyl peroxide (BP) (13.3%) were by far the most commonly used. Sunscreen (7.4%), Polysporin® (7.1%), and salicylic acid (5.8%) accounted for a significant proportion of OTC use as well (Table 4). HC was also the most commonly used topical OTC by non-dermatologists, but was used nearly twice as often by non-dermatologists (32.6%) relative to dermatologists (16.9%) (Table 5). Other common topical OTCs used by non-dermatologists included clotrimazole (9.3%), neomycin/polymyxin/bacitracin (7.2%), and bacitracin (5.4%), all of which were used with greater frequency in comparison to use by dermatologists (Table 6). BP (3.1%) was also used by non-dermatologists but not nearly as often as dermatologists (13.3%). There were more complementary topical OTC products, such as moisturizers, in the top 20 products recommended by dermatologists as compared to non-dermatologists.
Topical OTC use by race revealed several notable similarities and differences (Table 7). HC and BP represent the top 2 most commonly used products across all races. Sunscreen use was more common in patients described as white (8.4%) compared to black (1.2%) and other (3.5%). Additionally, polymyxin/bacitracin use was higher in patients categorized as white (8.0%) compared to black (0.9%) and other (3.2%). Conversely, hydroquinone use was higher in patients categorized as black (10.6%) and other (9.1%) in comparison to white (2.0%).
Examination of topical OTC use by diagnosis demonstrates several findings. BP represents the most commonly used product in the treatment of acne (55.1% of all OTCs). Complementary products, such as Neutrogena® (2.9%), Cetaphil® (2.7%), and sunscreen (1.6%) ranked among the top 10 most commonly used products for acne. For atopic dermatitis (AD), HC (41.5%) was the most commonly used, followed by Cetaphil® (13.7%), Eucerin® (9.3%), and Lubriderm® (4.4%). Unspecified dermatitis or eczema was treated similarly: HC (41.5%) was the most commonly used followed by Cetaphil® (9.0%) and Aquaphor® (5.4%). For psoriasis, tar (25.7%), salicylic acid (23.5%), and HC (18.0%) were the most commonly used. Rosacea was most commonly treated with, HC (30.3%), followed by sulfacetamide (21.8%), sunscreen (12.4%) and BP (10.9%) (Table 8).
Data demonstrated that dermatologists recommend moisturizers more frequently than non-dermatologists, overall. In managing AD, moisturizers were used nearly twice as often at dermatology visits (16.1%) in comparison to visits to all other specialties (8.8%). Similar trends were identified in patient visits for “unspecified dermatitis or eczema” and psoriasis, in which moisturizers were used more often by dermatologists than by other providers (Table 9). One notable exception to the general trend was in the case of keratoderma for which dermatologists use OTC moisturizers less (2.2%) than non-dermatologists (10.7%).
Linear regression analysis revealed that topical OTC use has changed over time. Among dermatologists, use has significantly decreased at a rate of approximately 0.44 percent per year (P<0.0001) (Figure 1). Topical OTC use has significantly decreased among non-dermatologists as well at a rate of 0.04 percent per year (p<0.0001) (Figure 2). Examining use of particular therapeutic categories identified several significant trends among dermatologists including an overall decreasing use of HC preparations (p<0.0001), anti-infectives (p=0.0001), keratolytics (p<0.004), and acne products (p<0.0001). Conversely, increasing use among dermatologists was observed for moisturizers (p<0.0001) and sunscreens (p=0.008).
Final analysis included a comparison of the top 10 most commonly used topical OTC products from 1989 to 1993, from 1994 to 1998, from 1999 to 2003, and from 2004 to 2008 (Table 10). During the first 5 years of the study, BP was the number one most frequently used topical OTC, accounting for 22.5 percent of all topical OTC use. However, in the last 5 years of the study, it dropped to 6.3 percent of all topical OTC use. Conversely, sunscreen ranked as the 5th most commonly used topical OTC skin product during the first 5 years of the study, accounting for and constituting 5.1 percent of all topical OTC use. During the last 5 years of the study, sunscreen increased to 12.8 percent and was the number one most commonly used topical OTC product.
Topical OTC products represent an important component of prevention and treatment of dermatologic conditions. This is underscored by the finding that over the 20-year study period, topical OTCs were recorded in approximately 320 million visits, of which dermatology visits accounted for nearly a third. As might be expected, dermatologists were most likely of all specialties to use topical OTC products, followed by general/family practitioners and pediatricians. This finding is consistent with earlier studies on topical OTC use .
Patients aged 0-9 years had the highest percentage of topical OTC use by a large margin. This may relate to the higher incidence in this population of skin conditions that naturally lend themselves to treatment with topical OTCs, including contact dermatitis, impetigo, diaper dermatitis, scrapes, and AD. Additionally, parents may be more at ease using topical OTCs products, which are not typically associated with worrisome side effects. Surprisingly, our analysis did not demonstrate a higher frequency of OTC use in self-pay patients. We expected more OTC use in this population to supplement the lack of prescription coverage. OTCs represent an economical therapeutic option for certain diagnoses, which may help in treating patients who cannot afford costly prescription medications. It is also possible that patients who have better insurance/prescription coverage are receiving OTCs as adjunctive treatments.
Comparing specific OTC products, HC and BP were by far the most commonly used OTCs by dermatologists. HC, a low potency corticosteroid with anti-inflammatory, anti-pruritic, and vasoconstrictive properties, has a variety of treatment indications, including many common inflammatory and pruritic dermatoses. It is specifically included in The American Academy of Dermatology (AAD)’s evidence-based guidelines for the management of both AD and psoriasis . Thus, it is no surprise that HC ranks as the number one most commonly used OTC by all specialties. Notably, use is much higher among non-dermatologists (32.6%) than dermatologists (16.9%), which may relate to the fact that dermatologists have more experience and greater comfort using higher potency agents as compared to non-dermatologists . In fact, studies have demonstrated that dermatologists are more likely than non-dermatologists to use high potency corticosteroids when indicated [11, 12]. There may also be a selection bias in that, while non-dermatologists may manage milder dermatologic conditions, whereas dermatologists are more likely to treat patients with more severe disease, warranting use of more potent corticosteroids.
BP, the 2nd most commonly used OTC by dermatologists, is a topical bactericidal agent. Whereas BP has a variety of uses, its role in the treatment of acne vulgaris, an exceedingly common dermatologic condition with an estimated prevalence of 5 million in the U.S., is what contributes most to its place as the number 2 most common topical OTC . The AAD’s 2007 evidence-based guidelines on the management of acne vulgaris recommend its use in conjunction with topical and systemic antibiotics [13, 14]. Although BP ranked 2nd among dermatologists (13.3%), it was used significantly less frequently by non-dermatologists (3.1%), ranking only 6th. Because dermatologists presumably treat more patients with acne, this distinction is no surprise.
Sunscreen ranked as the 3rd most common OTC used by dermatologists, which reflects a growing emphasis on skin cancer prevention. However, sunscreen did not even make the top 20 list for non-dermatologists, which warrants some attention considering that primary care providers may have the greatest opportunity to educate patients and make recommendations for preventive health, including prevention of skin cancer.
Also of note, the use of topical antibiotics varied between dermatologists and non-dermatologists. Whereas bacitracin, polymyxin/bacitracin, and neomycin/polymyxin/bacitracin appear on the top 20 OTC lists for all physicians, they account for a greater proportion of overall topical OTC use by non-dermatologists (14.9%) than by dermatologists (12.2%). In addition, non-dermatologists favored neomycin/polymyxin/bacitracin, whereas dermatologists favored polymyxin/bacitracin. Use of neomycin/polymyxin/bacitracin was much more common among non-dermatologists, ranking 3rd among OTCs used (7.2%), whereas dermatologists used neomycin/polymyxin/bacitracin the least of all the topical antibiotics available (1.2%). Neomycin, one of the active ingredients of this triple antibiotic is a potent contact allergen that has received considerable attention in the dermatologic literature; dermatologists may have reservations about using this antibiotic. Other physicians’ higher use of neomycin/polymyxin/bacitracin may simply be a result of decreased awareness of its potential for inducing allergic contact dermatitis [15, 16].
Analysis of popular topical OTC products associated with common skin conditions demonstrates several interesting findings. BP was by far the most commonly used product in the treatment of acne. This finding is consistent with the AAD’s guidelines for the treatment of acne. It is reassuring that sunscreen ranked in the top 10 OTCs by this diagnosis because sun protection is especially important in this population because of age and the simultaneous use of medications that may induce photosensitivity. Findings in AD and unspecified dermatitis or eczema are similar, with HC ranking highest and various moisturizers and/or keratolytics following. This is unsurprising because these are corticosteroid-responsive dermatoses and also benefit from complementary moisturizer use for repair of the epidermal barrier. Topical OTCs associated with psoriasis include tar, salicylic acid, and HC. The use of HC is not surprising because topical corticosteroids are class A recommendations for the topical treatment of psoriasis by the AAD . The use of tar and salicylic acid in conjunction with topical corticosteroids are also recommended but received a lower level of evidence-based recommendation .
Moisturizers serve as important adjunctive therapeutic modalities for many chronic skin conditions, including AD and psoriasis, and constitute part of evidence-based guidelines for the treatment of these conditions . In the present study, dermatologists recommended moisturizers more often than non-dermatologists, which may be secondary to dermatologists’ greater experience in treating skin disease and greater knowledge of and comfort with recommending complementary products. This discrepancy was especially pronounced in the management of AD, in which dermatologists used moisturizers nearly twice as often as non-dermatologists. Clinical studies demonstrate that the use of moisturizers confers numerous therapeutic benefits including: improving skin hydration, reducing irritation, and restoring integrity of the stratum corneum [18, 19]. The use of moisturizers in AD patients is essential to restore and maintain the function of the stratum corneum and is the standard of care in the management of these patients . Whereas dermatologists appear to be doing a better job of following this evidence-based guideline relative to non-dermatologists, neither are doing very well; dermatologists recommended moisturizer use in only 16.1 percent of all AD visits. All physicians managing AD should be encouraged to recommend moisturizers at every AD visit in compliance with current treatment guidelines.
Moisturizers also have an important role in the management of psoriasis, improving desquamation and hydration [12, 19]. Additionally, they enhance the efficacy of topical corticosteroids, thereby exerting a steroid-sparing effect . In the present study, moisturizer use for psoriasis was much lower than expected, recorded in only 2.7 percent of dermatology visits and not at all in visits to all other physicians. This suggests that both dermatologists and non-dermatologists managing psoriasis should work to increase their moisturizer recommendations for psoriasis patients to optimize treatment outcomes. Whereas in the present study dermatologists used moisturizers more than did non-dermatologists overall, a notable exception was in the treatment of acquired keratoderma. Among these patients moisturizers were used in only 2.2 percent of dermatology visits, but in 10.7 percent of non-dermatology visits. This finding may reflect dermatologists’ increased comfort and experience with a broader arsenal of more effective active agents for the treatment of keratoderma (keratolytics, topical vitamin D ointment, topical retinoids, and/or systemic retinoids), in comparison to non-dermatologists.
Linear regression analyses revealed a significant decrease over time in use of topical OTC products by all physicians. This may relate to the development of more effective prescription treatments, patient preference for more potent medications, and the development of better tolerated formulations of prescription medications . This downward trend was borne out when looking at specific product use among dermatologists as well. HC is decreasing, likely secondary to increased use of more potent topical corticosteroids that achieve better control of dermatologic conditions such as psoriasis and AD. Anti-infectives are being used less perhaps because of the accumulation of evidence demonstrating that the indications for such products is quite limited and that these agents, particularly neomycin and bacitracin, are common causes of allergic contact dermatitis [15, 16]. The decreasing use of keratolytics parallels recent challenges in the literature to classic teaching that keratolytics are essential to remove excess scale from thick scaly psoriatic plaques to increase penetration of topical corticosteroids. Clinical trials have shown that plaques respond well to topical corticosteroids independent of keratolytic use [21, 22, 23, 24]. Finally, the significant decrease in use of OTC acne products may be attributable to the availability of new combination products containing BP, topical antibiotics, and/or retinoids [14, 25]. Prescription combination topical medications often eliminate the need for an adjunctive OTC product like BP. They reduce the potential for P. acnes resistance and enhance efficacy [26, 27, 28, 29]. These products are useful in addressing multiple pathogenic factors, contribute to better tolerability, simplify treatment regimens, promote adherence, and are more effective than single agents, thus maximizing patient outcomes [14, 26-30].
Whereas the majority of topical OTC products are being used with decreasing frequency, the present study revealed significantly increasing trends in the use of moisturizers and sunscreens among dermatologists. The increase in moisturizer use may be secondary to a growing body of evidence and improved understanding of the integral role of moisturizers as adjunctive therapies for patients with a variety of dermatologic diseases including acne, rosacea, AD, and psoriasis [18, 19, 31]. Sunscreen use by dermatologists has increased significantly over the 20-year study interval, likely in response to the increasing incidence and prevalence of skin cancer in the U.S. and reflects an increasing emphasis on primary prevention [32, 33].
The present study is limited by the nature of the NAMCS database. Data is cross-sectional and limited to outpatient visits. OTC products and medications are recorded by name for each patient visit; no distinction is made whether a medication or product is being newly recommended or was prescribed previously. Similarly, there is no information besides the name to distinguish whether a product is OTC or prescription. Thus, products available in both OTC and prescription formulations, but bearing the same name like HC, could not be distinguished. Therefore, the data may overestimate OTC use for these products. Finally, it was assumed that if a specific OTC product was not documented in the database that it was not being used. Whereas providers participating in the NAMCS are instructed to record all products being used or recommended at a visit, including OTCs, there may be underreporting of OTC use, which would result in underestimates of OTC use.
OTCs, as therapeutic agents and as complementary products, represent important tools in the treatment and prevention of many common dermatologic conditions. This study demonstrates the widespread use of OTC products by U.S. physicians, in particular, dermatologists. In addition, it provides an important characterization of the ways in which OTCs are used in the management of dermatologic conditions and identifies areas for potential improvement in utilization of topical OTCs to optimize dermatologic health care outcomes for our patients.
References1. Regulation of nonprescription products. Food and Drug Administration. 2011. Ref Type: Internet Communication
2. Attitudes and beliefs about the use of over-the-counter medicines: a dose of reality. Harris Interactive/National Council on Patient Information and Education. 2011. Ref Type: Internet Communication
3. Primary prevention in the adult. American Heart Association. 2011. Ref Type: Internet Communication
4. OTC Retail Sales - 1964-2009. Consumer Health Products Association . 2011. Ref Type: Internet Communication
5. Kaufman DW, Kelly JP, Rosenberg L, Anderson TE, Mitchell AA. Recent patterns of medication use in the ambulatory adult population of the United States: the Slone survey. JAMA 2002;287:337-44. [PubMed]
6. Johnson ML. Defining the burden of skin disease in the United States--a historical perspective. J Investig Dermatol Symp Proc 2004;9:108-10. [PubMed]
7. Fleischer AB, Jr., Feldman SR, Bradham DD. Office-based physician services provided by dermatologists in the United States in 1990. J Invest Dermatol 1994;102:93-7. [PubMed]
8. OTC Sales by Category - 2006-2009. Consumer Health Products Association . 2011. Ref Type: Internet Communication
9. Vogel CA, Balkrishnan R, Fleischer AB, Cayce KA, Feldman SR. Over-the-counter topical skin products--a common component of skin disease management. Cutis 2004;74:55-67. [PubMed]
10. Hanifin JM. Guidelines of care for atopic dermatitis. American Academy of Dermatology. 2011. Ref Type: Internet Communication
11. Stern RS. The pattern of topical corticosteroid prescribing in the United States, 1989-1991. J Am Acad Dermatol 1996;35:183-6. [PubMed]
12. Friedlander SF, Hebert AA, Allen DB. Safety of fluticasone propionate cream 0.05% for the treatment of severe and extensive atopic dermatitis in children as young as 3 months. J Am Acad Dermatol 2002;46:387-93. [PubMed]
13. Strauss JS, Krowchuk DP, Leyden JJ, Lucky AW, Shalita AR, Siegfried EC et al. Guidelines of care for acne vulgaris management. J Am Acad Dermatol 2007;56:651-63. [PubMed]
14. Harper JC. Benzoyl peroxide development, pharmacology, formulation and clinical uses in topical fixed-combinations. J Drugs Dermatol 2010;9:482-7. [PubMed]
15. Sheth VM, Weitzul S. Postoperative topical antimicrobial use. Dermatitis 2008;19:181-9. [PubMed]
16. Messingham MJ, Arpey CJ. Update on the use of antibiotics in cutaneous surgery. Dermatol Surg 2005;31:1068-78. [PubMed]
17. Menter A, Korman NJ, Elmets CA, Feldman SR, Gelfand JM, Gordon KB et al. Guidelines of care for the management of psoriasis and psoriatic arthritis. Section 3. Guidelines of care for the management and treatment of psoriasis with topical therapies. J Am Acad Dermatol 2009;60:643-59. [PubMed]
18. Ghali FE. Improved clinical outcomes with moisturization in dermatologic disease. Cutis 2005;76:13-8. [PubMed]
19. Draelos ZD. Concepts in skin care maintenance. Cutis 2005;76:19-25. [PubMed]
20. Stern RS, Nijsten T, Feldman SR, Margolis DJ, Rolstad T. Psoriasis is common, carries a substantial burden even when not extensive, and is associated with widespread treatment dissatisfaction. J Investig Dermatol Symp Proc 2004;9:136-9. [PubMed]
21. McClain R, Yentzer BA, Feldman SR. Keratolytics for psoriasis: are they necessary? Dermatol Online J 2009;15:11. [PubMed]
22. Katz HI, Lindholm JS, Weiss JS, Shavin JS, Morman M, Bressinck R et al. Efficacy and safety of twice-daily augmented betamethasone dipropionate lotion versus clobetasol propionate solution in patients with moderate-to-severe scalp psoriasis. Clin Ther 1995;17:390-401. [PubMed]
23. Andreassi L, Giannetti A, Milani M. Efficacy of betamethasone valerate mousse in comparison with standard therapies on scalp psoriasis: an open, multicentre, randomized, controlled, cross-over study on 241 patients. Br J Dermatol 2003;148:134-8. [PubMed]
24. Griffiths CE, Finlay AY, Fleming CJ, Barker JN, Mizzi F, Arsonnaud S. A randomized, investigator-masked clinical evaluation of the efficacy and safety of clobetasol propionate 0.05% shampoo and tar blend 1% shampoo in the treatment of moderate to severe scalp psoriasis. J Dermatolog Treat 2006;17:90-5. [PubMed]
25. James KA, Burkhart CN, Morrell DS. Emerging drugs for acne. Expert Opin Emerg Drugs 2009;14:649-59. [PubMed]
26. Chalker DK, Shalita A, Smith JG, Jr., Swann RW. A double-blind study of the effectiveness of a 3% erythromycin and 5% benzoyl peroxide combination in the treatment of acne vulgaris. J Am Acad Dermatol 1983;9:933-6. [PubMed]
27. Tschen EH, Katz HI, Jones TM, Monroe EW, Kraus SJ, Connolly MA et al. A combination benzoyl peroxide and clindamycin topical gel compared with benzoyl peroxide, clindamycin phosphate, and vehicle in the treatment of acne vulgaris. Cutis 2001;67:165-9. [PubMed]
28. Leyden JJ, Hickman JG, Jarratt MT, Stewart DM, Levy SF. The efficacy and safety of a combination benzoyl peroxide/clindamycin topical gel compared with benzoyl peroxide alone and a benzoyl peroxide/erythromycin combination product. J Cutan Med Surg 2001;5:37-42. [PubMed]
29. Lookingbill DP, Chalker DK, Lindholm JS, Katz HI, Kempers SE, Huerter CJ et al. Treatment of acne with a combination clindamycin/benzoyl peroxide gel compared with clindamycin gel, benzoyl peroxide gel and vehicle gel: combined results of two double-blind investigations. J Am Acad Dermatol 1997;37:590-5. [PubMed]
30. Draelos ZD. Improving compliance in acne treatment: benzoyl peroxide considerations. Cutis 2008;82:17-20. [PubMed]
31. Bikowski J. The use of therapeutic moisturizers in various dermatologic disorders. Cutis 2001;68:3-11. [PubMed]
32. Linos E, Swetter SM, Cockburn MG, Colditz GA, Clarke CA. Increasing burden of melanoma in the United States. J Invest Dermatol 2009;129:1666-74. [PubMed]
33. Cancer facts and figures 2010. American Cancer Society. 2011. Ref Type: Internet Communication
© 2012 Dermatology Online Journal