Ample research establishes that acne can have a strong psychosocial impact on affected patients¹ and suggests that its influence on quality of life may be similar to that of asthma or epilepsy.² The link between acne and an individual's emotional and functional status has been described as “causal, and at times reciprocal.”³ Importantly, improvement of acne is associated with improvement in self-esteem, shame, embarrassment, body image, self-confidence, and other psychosocial measures.¹

When considering the psychosocial impact of acne vulgaris, individuals may tend to think of facial acne—the most common and often the most visible form of acne. However, back and chest acne have been estimated to occur in 61 percent and 45 percent of acne patients, respectively,⁴ and truncal acne is also associated with a significant psychosocial impact.⁵ Given this potential impact and the recognition that some patients do not even realize they have truncal involvement,⁴ clinicians should be more attentive to truncal acne and prepared to provide appropriate treatment, a notorious clinical challenge.

Perspective on Truncal Acne
Although data on truncal acne are limited, one study of patients referred to a dermatology clinic revealed that more than 60 percent of individuals had back acne.⁴ In another cohort of 696 patients from five cities, half of patients with facial acne were found to have coexistent truncal involvement, while three percent of patients had truncal acne only.⁶

Of note, these studies revealed that patients may be unaware either of truncal involvement or the availability of treatments for it. In the first study, 35 percent of subjects who reported no back involvement were found on exam to have back acne. Similarly, 33 percent of subjects reporting no chest involvement were found to have chest acne.⁴ In the second study, roughly one out of four patients failed to mention truncal involvement; it was detected by clinical observation.⁶ These findings suggest that, in addition to simply questioning patients about truncal involvement, observation of these sites during the initial office visit may be indicated.

The impact of truncal acne on self-consciousness cannot be overlooked. Survey responses from 132 individuals reporting to a specialty clinic for acne care revealed that back acne negatively impacted sexual and bodily self-consciousness of appearance in both men and women. Also of note in this study was that acne, regardless of site of involvement, seemed to more significantly impact the self-consciousness of individuals age 20 or older compared to those age 16 to 19.⁷

Pathophysiologically, truncal acne is no different from acne on the face, although the chest, back, and shoulders may be more prone to “acne mechanica.”⁸ The effects of pressure, occlusion, friction, and heat produced by shoulder pads and other sports equipment may contribute to exacerbation of acne. In addition to targeted anti-acne therapies, strategies to minimize the mechanical forces of equipment should be instituted when acne mechanica is present or suspected.

Acne on the back and chest is expected to respond to therapy just as acne on the face would. Nonetheless, evidence suggests that dermatologists tend to frequently prescribe oral therapies for truncal acne,9 likely because systemic therapy is assumed to be more convenient than topical applications to these large and potentially hard-to-reach body areas. The challenges of topical application to the trunk, particularly the back, are obvious, making patient compliance a challenge. Acne is already associated with compliance difficulties.10 However, several topical therapies may be appropriate for application to the trunk.

Antimicrobial cleansers and washes, specifically those containing benzoyl peroxide, have been a convenient option to treat truncal acne for some time. They are shown to be effective and associated with low rates of irritation,11 however benzoyl peroxide wash monotherapy may not yield optimal results.

Topical clindamycin has been a mainstay of acne therapy. One attempt to ease application to the back and improve compliance with topical antibiotic therapy is a novel device ClindaReach (DUSA Pharmaceuticals), a wand-type device designed to aid application of clindamycin solution 1% via pledgets. Home-health catalogs market various devices intended to aid application of topical agents to hard-to-reach body sites (usually they are marketed to older patient for bathing or application of lotions), and these may prove useful for application of any topical therapy to the back or other sites.

Clindamycin phosphate foam 1% (Evoclin, Stiefel) is another relatively new agent specifically formulated for use to manage acne on the trunk. In clinical studies, clindamycin foam was superior to clindamycin gel or the foam vehicle in reduction in total, inflammatory, and noninflammatory acne lesion counts.¹²

Foam vehicles have become popular in recent years, as they are associated with improved usability, better compliance and, consequently, improved therapeutic results.13 The newest foam formulation approved for acne is a benzoyl peroxide 5.3% emollient foam (BenzEFoam, Onset Therapeutics), which has been shown to produce a 100-fold reduction in P. acnes colonization after two weeks of use.¹⁴

Benzoyl Peroxide Rediscovered
Used for the treatment of acne since the 1930s, benzoyl peroxide has been a mainstay of therapy, though it was largely relegated to the over-thecounter market for many years. Renewed focus on the benefits of benzoyl peroxide may be attributed in part to the fact that it is directly toxic to P. acnes and is not associated with the development of resistance.11 While topical benzoyl peroxide can be irritating to the skin, the use of lower concentrations and newer vehicle formulations has been shown to minimize this irritation potential while maintaining efficacy. Benzoyl peroxide may be used as monotherapy or in conjunction with other antibacterial and/or retinoid preparations; combination regimens that target multiple pathogenic factors are frequently indicated in topical acne therapy.¹⁵

In clinical trials, BenzEFoam was associated with low rates of irritation, with no treated patients reporting drying or flaking.¹⁴ BenzEFoam contains micronized benzoyl peroxide particles that are intended to be naturally solubilized by sebum, leading to a gradual release of drug into the sebaceous follicles. Repeat insult patch testing showed that the micronized BPO is non-irritating.¹⁴ Ingredients in the vehicle, such as dimethicone and glycerin, are known skin protectants and emollients, respectively. The hydrating effects of the new emollient foam formulation of benzoyl peroxide 5.3% may contribute to enhanced tolerability.

In a study comparing the hydrating effects of benzoyl peroxide 5.3% foam to those of a gel combination formulation of clindamycin 1% and benzoyl peroxide 5%, the foam showed statistically significantly greater skin hydration than the gel at all studied time points up to eight hours after application.¹⁴ Mean moisture values for the foam were nearly six-times higher than those for the gel at one hour and more than three-times higher at eight hours.

Data indicate that benzoyl peroxide emollient foam 5.3% may confer benefits over benzoyl peroxide wash 8%. A five-week, open-label, single center study enrolled 20 patients with P. acnes on their back (at least 10,000 colonies per cm²).16 Subjects applied the BPO foam to their backs daily during weeks 1 and 2, applied no products during week 3, and then applied BPO wash daily during weeks 4 and 5. Total P. acnes counts were reduced by 1.8 log at the end of week 1 and by 2.1 log at the end of week 2. Counts returned to baseline by the end of week 3 (washout). Use of BPO wash produced no reduction in P. acnes counts at weeks 4 or 5.

One limitation of the study is that while application of the foam was supervised in the clinic, use of the wash was done at home without supervision. Lack of compliance or improper application of the wash could account for some disparity in performance.

Dr. Bikowski has served on the advisory board, served as a consultant, received honoraria, and/or served on the speaker's bureau for Allergan, Barrier, CollaGenex, Coria, Galderma, Intendis, Medicis, OrthoNeutrogena, PharmaDerm, Quinnova, Ranbaxy, Sanofi-Aventis, SkinMedica, Stiefel, UCB, and Warner Chilcott.

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