Treatment of Inflammatory Facial Acne Vulgaris with the 1450-nm Diode Laser

Keywords:surgical, fibers,  Time:25-04-2016

The pathogenesis of acne is multifactorial. The initiating factor is thought to be the formation of a keratinous plug in the infundibulum of hair follicles as a result of abnormal differentiation and desquamation of follicular keratinocytes. The transformation of comedones into inflammatory lesions is due to proliferation of Propionibacterium acnes bacteria within the keratin plug, which are capable of metabolizing trapped sebum into proinflammatory free fatty acids. Mild acne often improves with various combinations of topical antimicrobials, retinoids, or keratolytics, which require frequent application and often result in irritation. Inflammatory disease often requires the long-term use of systemic antibiotics, and more severe disease may require systemic isotretinoin, which is associated with numerous untoward and potentially serious side effects. Many patients require continuous treatment with topical and oral medications for months or years. Moreover, despite the use of individual and combination therapies, patients often continue to develop new lesions for years. The use of photothermal therapy is driven by the need for a safer, more effective, and more convenient treatment for acne. These therapies may help avoid side effects associated with both topical and systemic therapies while reducing the need for compliance with complicated regimens. These treatments are administered by physicians at relatively infrequent intervals or even on an as-needed basis. Initial light-based therapies for acne relied on the absorption of specific wavelengths of visible light by endogenous porphyrins produced by P. acnes.3 Photoactivation of porphyrins results in lethal oxidative damage to the bacteria, resulting in reduction of P. acnes colonization and a reduction in inflammatory acne lesions. Photodynamic therapy with 5-aminolevulinic acid has been introduced for the treatment of acne in order to augment this phenomenon.4 More recently, the 1450-nm diode laser has been used for the treatment of acne on the back.

Paithankar et al.5 showed through heat transfer calculations and histologic verification on rabbit ear skin that the 1450-nm diode laser, with its wavelength in the infrared range, specifically targets thermal damage to the middermal layer of the skin, where the sebaceous glands are primarily located. The concurrent use of a cryogen spray device protected the epidermis from thermal damage. The use of this laser in patients was associated with a clinically and statistically significant reduction in acne lesions on the back. The only associated side effects were transient erythema and edema. As inflammatory facial acne is the most common reason for patients seeking treatment for acne, we performed a study to evaluate the safety and efficacy of the 1450-nm diode laser with a cryogen spray device for the treatment of inflammatory facial acne vulgaris. To our knowledge, this is the first published report of the use of lasers to treat inflammatory facial acne vulgaris.

Methods

Nineteen patients (12 women and 7 men) with active inflammatory facial acne with Fitzpatrick skin phototypes II–IV were enrolled in the study. The presence of at least five active inflammatory lesions was required. The age range was 15 to 44years (mean 26  7). Exclusion criteria included pregnancy, treatment with oral isotretinoin within the past 6 months, or the use of dermal fillers within the past 3months. Patients were allowed to continue previous medications during the study. These medications included topical agents (antibiotics and retinoids) as well as oral antibiotics such as doxycycline. Seven patients had previously completed courses of oral isotretinoin.

Topical lidocaine 5% (Ela-Max; Ferndale Laboratories, Ferndale, MI) was applied under occlusion 1 hour before laser treatment to patients requesting provision of topical anesthesia. The entire face was treated with nonoverlapping single pulses of a 1450nm diode laser (Smoothbeam; Candela Corporation, Wayland, MA) with an integrated dynamic cooling device. Treatment fluences ranged from 11 to 14J/cm2, delivered using a 6-mm spot size. The dynamic cooling device setting was set at 40ms to cool the epidermis. Immediately after the treatment, a moisturizing cream and sunscreen were applied to the treated skin. Based on previous studies, treatments were separated by a 4- to 6-week period.