Significant improvements were observed in acne lesions on the treated sides of patients' faces and a significant reduction in the total number of acne lesions was observed on the treated side when compared with the untreated side. These data also indicate that after the final treatment session, measurable improvements were noted in inflammatory lesions on the treated side of the face, an effect that persisted to the final follow-up visit at 12 weeks.
Among the individuals who opted for additional treatment on the contralateral side of the face, a marked improvement was seen in both inflammatory and non-inflammatory acne lesions, a difference that reached statistical significance when compared with the state before treatment. We contend that the greater degree of improvement observed among these individuals results primarily from self selection: subjects who achieved effective treatment results were more inclined to request additional treatments on the untreated side.
No severe side effects occurred during this study. In fact, the only adverse events reported were transient erythema, purpura and acne flare. The petechiae that occurred in one patient developed in an area between the nasal bridge and inner canthus. Although all evidence of petechiae had vanished within 1 week after treatment, we did not subject this area to treatment in any other patients, and would advise other providers to use caution when treating this anatomic region. According to Wanitphakdeedecha et al.5
, most patients experienced acne worsening early in the treatment course during their photopneumatic treatment study. They suggest that causes of lesional worsening include incomplete comdone removal or comedonal rupture during application of negative pressure, leading to development of tissue inflammation and inflammatory lesions. Five patients showed acne flare after 1st treatment session at our study ().
Interestingly, while several articles have suggested that photopneumatic therapy is an effective method for evacuating sebum, we rarely observed expelled sebum at the cheek area that is main site of acne. The expelled sebums were occasionally observed at the nose area where there was a pre-existing dilated pore. Nonetheless, significant reductions in noninflammatory acne were observed after photopneumatic treatment despite the lack of any obvious sebum extraction. We contend that the therapeutic mechanism of photopneumatic device on acne lesions is more closely related to the phototherapeutic effect of the device rather than the pure physical mechanics.
have suggested that IPL is not an effective treatment modality for acne in patients of Asian descent. However, these studies employed IPL device light sources with wavelengths set at greater than 560 nm. Furthermore, such devices only emitted light in the yellow and red regions (550~800 nm), thus lacking any blue region wavelengths (400~500 nm). Conversely, the study by Kawana et al.3
demonstrated that IPL (400~700 nm and 870~1,200 nm, 13 J/cm2
, 5 sessions at 1 week interval) does have a potent therapeutic effect on both inflammatory and non-inflammatory acne lesions in Asians. Our device has a broadband light source (400 nm to 1,200 nm), thereby including all blue light regions6
Coproporphyrin III, the major endogenous porphyrin of Propionibacterium acnes
, absorbs light in both the ultraviolet A (320~400 nm) and blue light spectra, with a maximum absorption near 415 nm7
. Accordingly, different ranges of light can produce vastly variable results. Although porphyrin absorption is strongest in the blue spectrum, these wavelengths penetrate the dermis poorly in vivo
. Facial sebaceous glands, one component of the follicular unit, are located approximately 0.5 mm to 1.0 mm below the cutaneous surface, thus the vacuum suction delivered by the photopneumatic device allows deeper light penetration than would be obtained with traditional blue light therapy. That wavelengths in the red light spectrum are significantly longer which may explain the greater efficacy of the IPL device. Similarly, there is ultrastructural evidence for thermal damage to pilosebaceous units and bacteria by the photopneumatic device8
. Mechanical extrusion of comedonal contents from the infundibulum has been observed histologically. Although we rarely found notable sebum removal by the vacuum mechanism at cheek area, it may have facilitated deeper light penetration in addition to minimal mechanical effect, thus reducing side effects and increasing treatment effectiveness. The combination of thermal effect, mechanical effect and vacuum effect might act comprehensively on the acne lesion.
Gold and Biron9
describe a study of seven patients with mild to moderate acne vulgaris who received 4 treatments with photopneumatic therapy at 3 week intervals. By the study end, significant reductions in both inflammatory and noninflammatory lesions had occurred at 3 months. In another study by Wanitphakdeedecha et al.5
photopneumatic therapy was administered to 20 patients at 2 week intervals, after which time a modest reduction in acne lesion counts and global clinical improvement were observed in the majority of patients. In both articles, no severe side effects occurred, with the most common adverse event encountered being mild pain and transient erythema.
However, no split-face trials were previously published. Therefore, by using a split-face format, we can definitively determine that any observed improvements in acne are the direct result of the photopneumatic treatment. We contend that photopneumatic treatment is an effective alternative treatment method for acne patients who must avoid oral medications. Busy patients may also especially benefit from this device because it can be used without topical anesthesia, and therefore significantly less time is required than with many other laser-based protocols. Compared to IPL therapy, there is virtually no blistering, burning or postinflammatory hyperpigmentation associated with photopneumatic therapy. Photopneumatic therapy is significantly more safe and effective. One limitation of this study is the small number patients enrolled, and additional; larger trials are clearly needed.