Chapter 7: Laser and Light Therapies for the Treatment of Acne Vulgaris

OVERVIEW

Acne vulgaris is a common, often chronic disease affecting 85% of teenagers and persisting in up to 50% of adults.^1–3 The psychosocial impact of acne is significant and has been shown to cause low self-esteem, depression, and decreased quality of life.^4,5 The estimated annual cost of acne treatment is over $1 billion in the United States.⁶ Conventional medical treatments for acne, both topical and oral, have side effects making them inconvenient and sometimes intolerable for patients. Thus, a search for other treatments has led to investigations on the effectiveness and tolerability of laser- and light-based therapies. In recent years usage of these devices has gained in popularity among dermatologists.⁷

Laser- and light-based treatments can be used to improve comedonal and inflammatory acne, oily skin, and acne scarring. Like the medical treatment of acne, laser and light therapies attempt to target key pathogenic factors producing acne lesions: sebum production by sebaceous glands, Propionibacterium acnes proliferation and inflammation, and follicular hyperproliferation.⁸ Depending on the wavelength and technique used, these devices are thought to work by directly killing P. acnes, damaging sebaceous glands, or both.⁹ P. acnes produce endogenous porphyrins within sebaceous glands. These porphyrins are activated by light energy to form reactive oxygen species that kill bacteria.¹⁰ Peak porphyrin absorptions lie in the visible light range, with maximal absorption in the blue light wavelength at 415 nm.¹¹ Blue, red, and green light individually decrease P. acnes counts without damaging sebaceous glands.¹⁰ It is thought that direct thermal damage to sebaceous glands occurs with the use of nonablative infrared lasers (1320, 1450, 1540 nm), as they have greater depth of penetration.¹² More recently, photopneumatic therapy combining vacuum suction and broadband light has been used to treat comedonal and inflammatory lesions.¹³

CHOOSING THE RIGHT LASER OR LIGHT SOURCE FOR THE LESION

It is important to choose the right laser or light source for the type of acne. Table 7-1 lists all the laser/light sources that have been studied for the treatment of acne vulgaris. Depending on the patient’s skin, a combination of these devices can be used, as well as combining these treatments with medical therapy. The following sections of this chapter will detail methods for using selected lasers that we use most commonly for the treatment of acne vulgaris.

Targeting Inflammatory ...