Laser treatment for hair loss

One of the most common types of hair loss is alopecia areata (AA). Areata alopecia is an autoimmune disease that is characterized by the phenomenon of hair loss in certain places on the head. Currently, a large number of treatment methods for AA are used, ranging from corticosteroid injections to local immunotherapy. Laser treatment of hair loss as an effective method of treatment began to be applied relatively recently with the study of “paradoxical hypertrichosis” described in patients who underwent laser hair removal. As a rule, “paradoxical hypertrichosis” was detected in patients using either low-energy lasers or lasers with a low degree of absorption of their radiation by melanin. Recent studies in this direction show the relationship between laser exposure and stimulation of follicular proliferation and differentiation of stem cells by increasing the level of heat shock proteins (HSF) and other factors that may play a role in the regulation of cell growth and differentiation under the influence of the laser. Moreover, the methods of using laser devices to stimulate hair growth are very different depending on the parameters of a particular laser system. We will consider the main laser systems that are used to treat hair loss, and primarily to treat AA, as the most common type of disease.

308 nm excimer laser

The active element of an excimer laser consists of xenon and chloride, emitting at a wavelength of 308 nm, lying in the region of medium ultraviolet (UVB). The mechanism by which an excimer laser achieves a therapeutic effect is still weakly emitted, but some manufacturers are actively positioning its use in trichology. Some experts believe that a wavelength of 308 nm induces apoptosis of T cells, thereby leading to an improvement in inflammatory diseases such as psoriasis. Because Since the autoimmune etiology of OA has a definite relationship with T-cell damage to hair follicles, there are prospects for the use of excimer lasers for the treatment of this type of disease. However, it should be noted that the high cost and insufficient number of studies and successful applications of excimer lasers for the treatment of baldness do not allow their use in widespread practice.

Photothermolysis by a pixel non-ablative laser

The most promising and widely used method is the use of non-ablative pixel laser. A fractional non-ablative laser (such as Nd: YAG laser 1320) is capable of creating multiple “microthermal treatment zones (MTZ)” that penetrate down to the reticular dermis without damaging the stratum corneum. As a result, a process begins similar to the wound healing process, which can cause hair growth. The main mechanisms for a pixel laser in the induction of hair regrowth are apoptosis of T cells and direct enhancement of hair growth due to stimulation of the circulatory nutritional structure of the hair.

Using a laser to accelerate drug absorption

Another indirect, but at the same time gaining popularity method of using lasers in trichology is the use of laser therapy to increase the absorption of drugs used in the treatment of OA and similar diseases. Effective absorption can be difficult due to the barrier function of the stratum corneum, and laser treatment is a controlled and non-contact method of accurately removing the stratum corneum without damaging the underlying structures. A number of studies are currently underway to study the efficacy of using Er: YAG laser to improve skin permeability for drugs used in alopecia. It was found that the use of a laser with an ablation depth of 6 and 10 μm increases the accumulation of minoxidil in the skin by 2–9 times, depending on the skin barriers used. A similar clinical study is conducted using radio frequency (RF) or fractional CO2 lasers with topical application of triamcinolone, followed by the use of acoustic pressure from an ultrasound wave, however, in most cases an erbium laser is preferable due to its higher accuracy of exposure. In addition to the ablation effect of removing the stratum corneum, laser radiation can interact with sebum, disrupting its barrier function, accelerating the absorption of drugs into the skin.

Despite the fact that the laser for the treatment of hair loss is not currently used as widely as for the treatment of other diseases, the emergence of new modern techniques opens up broad prospects in this direction.