therapy with BPO 9.8% foam reduced C. acnes counts on the back, whereas BPO 8% wash did not, which may be attributed to wash formulations likely not achieving adequate contact times.29 Bikowski found BPO 5.3% foam used as leave-on or as short-contact therapy for 5 minutes to be effective in truncal acne patients.30 A study assessing 40 patients with truncal acne of moderate severity treated with BPO 8% wash or BPO 9% cleanser over a 4-week period showed a reduction in inflammatory lesions of 37.23% and 30.19%, respectively, and non-inflammatory lesions of 28.03% and 25.23%, respectively.31-32 BPO 8% wash in combination with clindamycin phosphate 1% foam also resulted in a mean total lesion count reduction of 70% in one study.31 While effective, application of BPO on the torso can lead to bleaching of clothing and bedding; thus negatively impacting use by patients.
Other topical antibiotics also have been assessed. A split-trunk study in 1976 showed an improvement in number of active lesions with erythromycin 1% as well as clindamycin 1% twice daily monotherapies after at least 8 weeks of treatment.33 A study assessing the effect of tetracycline twice daily on acne of the chest and back did not find any significant improvement.34
Oral antibiotics also are a staple for management of truncal acne, especially in the reduction of inflammatory lesions. One study showed efficacy of the macrolide azithromycin 250 mg 3 times per week over a 4-week period in patients with truncal acne who had shown poor results with prior regimens.35 An open retrospective study assessed the effect of oral trimethoprim 300 mg twice daily along with topical clindamycin 1% lotion twice daily in 56 patients who failed to respond to a minimum of 2 courses of antibiotics. After at least 4 months of treatment, this combination led to an improvement of acne on the face, back, and chest.36 A long-term 6-month interventional trial in 204 patients with predominately facial or truncal acne treated with oral erythromycin 1 g daily or minocycline 200 mg daily given in combination with topical benzoyl peroxide showed that both antibiotic regimens improved truncal acne, albeit to a significantly less extent than facial acne.37 These results confirmed the earlier outcome by Greenwood et al who treated truncal acne patients with oral erythromycin for 6 months.38 They found a dose-dependent response of erythromycin with a 1 g daily dosing to be superior to a 500 mg daily dosing, with females responding better than males. Few studies also assessed the benefit of oral minocycline but those that did found truncal acne to be less responsive than facial acne.39 A single study investigated the use of oral doxycycline 100 mg twice daily either with BPO 9% cleanser and clindamycin 1% foam daily or BPO 9% cleanser only.40
Retinoids
Retinoids signal through retinoid acid receptors (RARs) and regulate transcriptional expression of numerous genes.41 Regulation of gene expression changes is unique to which RARs/RXRs are engaged, and these effects have been studied across numerous skin cell types.42-44 In general, retinoids exert anti-inflammatory effects, promote normal keratinization and keratinocyte differentiation, and regulate sebum production, thus impacting 3 of the 4 critical factors in acne pathogenesis.45
Goulden et al found intermittent use of oral isotretinoin 0.5 mg/kg/day for 1 week every 4 weeks for a total period of 6 months to be beneficial in truncal acne.46 However, they found a higher relapse rate in patients with predominantly truncal acne compared to facial acne after 12 months. Cunliffe et al also found topical isotretinoin 0.1% cream to be efficacious after 4 weeks of treatment.47
Procedural Management
Non-medical interventions have also successfully been used for the management of acne vulgaris. These include chemical peels, light devices, and laser therapies.48 Photodynamic therapy (PDT) has been assessed in patients with truncal acne.49 One pilot study found benefit of a single treatment session of PDT (red light source at wavelength 630 nm) with 5% aminolevulinic acid (ALA) under occlusion for 3 hours for truncal acne in 15 Asian patients with an overall 64.2% and 24.3% reduction in inflammatory and non-inflammatory lesion counts, respectively.50 Del Duca et al found PDT with 5% ALA to be of benefit when administered 4 times at 14-day intervals.51 Fabbrochini et al also used red light PDT with 15% ALA to the back and chest at 2-week intervals in 3 sessions.52 Another study performed a randomized split-body study of PDT using intense pulsed light (IPL) with liposomal methylene blue and found this combination to be superior to IPL alone on the back.53 Similarly, IPL with a 560-nm cut-off filter and 5% ALA was found to be superior to IPL alone with monthly sessions over 3 months.54 IPL monotherapy with cut-off wavelength of 400 nm over 4 sessions with 2-week intervals was also shown to be of benefit for patients with Fitzpatrick skin types II or III with moderate to severe acne of the chest and back.55
Other topical antibiotics also have been assessed. A split-trunk study in 1976 showed an improvement in number of active lesions with erythromycin 1% as well as clindamycin 1% twice daily monotherapies after at least 8 weeks of treatment.33 A study assessing the effect of tetracycline twice daily on acne of the chest and back did not find any significant improvement.34
Oral antibiotics also are a staple for management of truncal acne, especially in the reduction of inflammatory lesions. One study showed efficacy of the macrolide azithromycin 250 mg 3 times per week over a 4-week period in patients with truncal acne who had shown poor results with prior regimens.35 An open retrospective study assessed the effect of oral trimethoprim 300 mg twice daily along with topical clindamycin 1% lotion twice daily in 56 patients who failed to respond to a minimum of 2 courses of antibiotics. After at least 4 months of treatment, this combination led to an improvement of acne on the face, back, and chest.36 A long-term 6-month interventional trial in 204 patients with predominately facial or truncal acne treated with oral erythromycin 1 g daily or minocycline 200 mg daily given in combination with topical benzoyl peroxide showed that both antibiotic regimens improved truncal acne, albeit to a significantly less extent than facial acne.37 These results confirmed the earlier outcome by Greenwood et al who treated truncal acne patients with oral erythromycin for 6 months.38 They found a dose-dependent response of erythromycin with a 1 g daily dosing to be superior to a 500 mg daily dosing, with females responding better than males. Few studies also assessed the benefit of oral minocycline but those that did found truncal acne to be less responsive than facial acne.39 A single study investigated the use of oral doxycycline 100 mg twice daily either with BPO 9% cleanser and clindamycin 1% foam daily or BPO 9% cleanser only.40
Retinoids
Retinoids signal through retinoid acid receptors (RARs) and regulate transcriptional expression of numerous genes.41 Regulation of gene expression changes is unique to which RARs/RXRs are engaged, and these effects have been studied across numerous skin cell types.42-44 In general, retinoids exert anti-inflammatory effects, promote normal keratinization and keratinocyte differentiation, and regulate sebum production, thus impacting 3 of the 4 critical factors in acne pathogenesis.45
Goulden et al found intermittent use of oral isotretinoin 0.5 mg/kg/day for 1 week every 4 weeks for a total period of 6 months to be beneficial in truncal acne.46 However, they found a higher relapse rate in patients with predominantly truncal acne compared to facial acne after 12 months. Cunliffe et al also found topical isotretinoin 0.1% cream to be efficacious after 4 weeks of treatment.47
Procedural Management
Non-medical interventions have also successfully been used for the management of acne vulgaris. These include chemical peels, light devices, and laser therapies.48 Photodynamic therapy (PDT) has been assessed in patients with truncal acne.49 One pilot study found benefit of a single treatment session of PDT (red light source at wavelength 630 nm) with 5% aminolevulinic acid (ALA) under occlusion for 3 hours for truncal acne in 15 Asian patients with an overall 64.2% and 24.3% reduction in inflammatory and non-inflammatory lesion counts, respectively.50 Del Duca et al found PDT with 5% ALA to be of benefit when administered 4 times at 14-day intervals.51 Fabbrochini et al also used red light PDT with 15% ALA to the back and chest at 2-week intervals in 3 sessions.52 Another study performed a randomized split-body study of PDT using intense pulsed light (IPL) with liposomal methylene blue and found this combination to be superior to IPL alone on the back.53 Similarly, IPL with a 560-nm cut-off filter and 5% ALA was found to be superior to IPL alone with monthly sessions over 3 months.54 IPL monotherapy with cut-off wavelength of 400 nm over 4 sessions with 2-week intervals was also shown to be of benefit for patients with Fitzpatrick skin types II or III with moderate to severe acne of the chest and back.55
EFFICACY OF TREATMENTS OF TRUNCAL ACNE IN CLINICAL TRIALS
Interventional clinical trials for acne vulgaris with efficacy
endpoints focusing on truncal acne have been lacking. Few
medications have been studied in clinical trials utilizing truncal
