**3. Evidence-based studies**

Analysis of the biomedical literature database, PubMed, using the terms "excimer" and "alopecia areata" revealed that 16 of 38 studies analyzed were clinical trials, and five of these were control trials. Some of these studied protocols are given in **Table 2**. Of the control trials, one included 16 participants with 99 patches of AA [21]. The author of this study concluded that the excimer laser was safe and effective in AA. However, its effect on hair regrowth might be delayed compared with intralesional corticosteroids.

In 2004, Gundogan C et al. successfully treated two patients whose AA had progressively worsened for 3 and 14 weeks. They had used a 308 nm xenon chloride excimer laser (dosage: 300–2300 mJ/cm2 per session). The entire affected area showed homogenous and thick hair regrowth after 11 and 12 sessions within a 9-week and 11-week period. Relapse was not reported during the 5 and 18 months [22].

Christian Raulin et al. reported that hair regrowth was achieved with the 308 nm xenon chloride excimer laser for AA of the scalp in a prospective side-by-side trial. One representative lesion was chosen; one-half of it was treated, and the other half remained untreated. Only the treated area showed hair growth; after 27 sessions over 3 months (200–4000 mJ/cm<sup>2</sup> , a cumulative dose of 52.6 J/cm<sup>2</sup> ), this was probably not a spontaneous remission [23].

A study published by Zakaria et al. tested nine patients with AA using a 308 nm excimer laser, started with 50 mJ/cm<sup>2</sup> less than the minimal erythema dose. Then, doses were increased from 50 mJ/cm<sup>2</sup> every two sessions. The treated lesion was irradiated twice a week for 24 sessions. Each lesion had an opposite side untreated target lesion serving as a control. The results of the study revealed that the 308 nm excimer laser can stimulate hair growth in all patients with partial AA. This proves the effectiveness of laser treatment and excludes the possibility of spontaneous hair


#### **Table 2.**

*Various studies have used 308 excimer laser/light in the treatment of alopecia areata.*

*Overview of the Role of 308 Monochromatic Excimer Phototherapy for the Treatment of Alopecia… DOI: http://dx.doi.org/10.5772/intechopen.108531*

regrowth. No relapse was noted in those patients who lost their hair over a follow-up period of 3 months. Moreover, no hair regrowth was observed in patients with either AA universalis (AAU) or AA totalis (AAT) [14].

In 2007, Al-Mutairi investigated the effect of the 308 nm excimer laser in the treatment of patchy AA. Eighteen patients, seven males and eleven females, with 42 recalcitrant patches (including one adult with AAT) were enrolled. The lesions were irradiated with the 308 nm excimer laser twice a week for 12 weeks. On each patient, one lesion was left as a control for comparison. New hair regrowth was observed in 17 (41.5%) patches, with 13 of the 18 lesions on the scalp showing a complete regrowth of hair. Lesions on the extremities failed to show a response. Atopic diathesis had an unfavorable effect on the outcome of treated patients. The author concluded that the 308 nm excimer laser is an effective therapeutic option for patchy AA of the scalp and some cases of patchy AA of the beard area. In contrast, it does not work for patchy AA of the extremities [24].

Ohtsuki et al. conducted a study to evaluate the effects of the 308 nm excimer lamp on three patients with single AA resistant to conventional therapy. They gave each of the three subjects the laser at two-weekly sessions. After 10 sessions, the hair growth rate in all three patients had returned to normal [25].

In a study conducted by Byun JW et al., 10 patients with AA were investigated, and the alopecic patch was divided into control and treated sides. The excimer laser was administered twice a week for 12 weeks. A therapeutic effect on AA was achieved, proven by photographs and phototrichogram [26].

In a clinical study of 11 patients with AAU conducted by Arakawa Y. et al., participants were treated with a 308 nm excimer light at 2-week intervals for more than 16 sessions. Four patients achieved good responses, and two patients exhibited poor responses. The authors concluded that the 308 nm excimer light therapy significantly affects some AAU patients resistant to other treatments and may be an alternative therapeutic option for AAU. The study suggested that the administration of a high radiation dose is required to achieve a strong inflammatory skin reaction [27].

In a prospective study, Alhamzawi evaluated the efficacy and safety of a 308 nm monochromatic excimer lamp in treating 18 patients with multiple AA. The treatment protocol consisted of two sessions per week for 12 weeks. The excimer safety was evaluated by objectively recording adverse reactions and patient satisfaction. Follow-up continued for 6 months after treatment to assess the level of recurrence. The results significantly affected resistant cases of multiple AA with considerable safety and tolerability (**Figure 1**) [17].

Fenniche S. et al. evaluated the efficacy and safety of combining topical khellin (a furanochromone photosensitizer whose chemical structure is close to that os psoralens) and 308 nm excimer light in the treatment of a refractory ophiasis, of 1-year evolution, in a 5-year-old boy. The trial showed complete hair regrowth with no recurrence one year later [28].

A controlled study by Li A., Meng X., et al. used a 308 nm excimer lamp with minoxidil in 38 patients with AA. Each alopecia lesion was divided into the control and treated sides. Topical minoxidil (2% solution) was used on both sides, with a 308 nm excimer lamp only added on the treated side. The primary objective of the study was to compare the number of hair growth on the treated and control sides. The results indicated that the number of hair growth on the treated side was significantly greater than that on the control side [29].

#### **Figure 1.**

*Two patients with alopecia areata successively treated by 308 excimer lamp, a & e baseline, b & f 4 weeks after treatment, d & h 12 weeks after treatment.*

#### **Figure 2.**

*Alopecia totalis treated by combined therapy of twice weekly 308 excimer light with monthly intramuscular triamcinolone acetonide.*

Alhamzawi Nabeel K. tested the effect of combining 308 excimer phototherapy with IM triamcinolone acetonide on 10 patients with alopecia totalis. All patients received monthly IM triamcinolone acetonide (TAC) for six pulses and twice-weekly excimer phototherapy for 24 sessions. Four patients (40%) achieved complete regrowth of hair (100% regrowth), and three patients exhibited a satisfactory response (>70% regrowth). Two patients reported an unsatisfactory response (>10 to <70% regrowth). The study showed that younger patients responded better, as did those with a shorter history of the disease (**Figure 2**) [30].

Notably, the combination treatment of 308 excimer with systemic therapy is superior to excimer monotherapy, especially for resistant AA cases [30].

*Overview of the Role of 308 Monochromatic Excimer Phototherapy for the Treatment of Alopecia… DOI: http://dx.doi.org/10.5772/intechopen.108531*
