Alopecia areata is a polygenic autoimmune disease causing hair loss, particularly during the anagen phase of hair growth This condition has a lifetime risk of about 2.1% of the world population and the cumulative incidence seems to rise linearly with age .

Patchy non scarring hair loss on the scalp is the most common clinical presentation, although it can also occur elsewhere . In addition to patchy Alopecia Areata , a more severe form, alopecia totalis , presents with diffuse hair loss across the scalp. In the most severe form, alopecia universalis , hair loss occurs on all areas of the body, including the beard, eyelashes, and extremities .

Alopecia Areata can have a large impact on patients' quality of life, causing both cosmetic and psychosocial distress. Studies on the impact of hair loss have shown high levels of self-consciousness, jealousy, embarrassment, depression, introversion, and decreased self-esteem .

Alopecia Areata can occur at any age, but it is most common among young and middle-aged people . Both sexes are equally affected. Several environmental factors have been suggested as triggering Alopecia Areata, including infection, drugs, trauma, and stress. Thyroid autoimmune disease, atopy, and vitiligo are commonly associated. Diverse physical or psychological insults may trigger the episodes of Alopecia Areata, but there is no evidence that they influence prognosis.

Etiology of Alopecia Areata is not completely understood, and the majority of evidence suggests that genetically predisposed individuals, when exposed to an unknown trigger, develop a predominantly autoimmune reaction, leading to acute hair loss.

Although many patients improve spontaneously or respond to standard therapy, treatment can be quite challenging in those with more severe and refractory disease .

Topical corticosteroids are often the first line of treatment for mild patchy alopecia, with the underlying mechanism being containment of inflammation and hastening of the recovery of damaged hair follicles . Additionally, corticosteroids may be delivered via intralesional injection with slightly better effects (63% with complete regrowth within 4 months in one study . However, this method cannot be used for rapidly progressing variants and does not prevent hair loss at other sites . Furthermore, both topical and intralesional steroids increase the risk of cutaneous atrophy at the site of treatment, and intralesional steroids may decrease bone mineral density .

With the development of new technologies, more and more lasers or lamps have been used to treat alopecia, such as ultraviolet , Excimer laser/lamp , low-level laser , erbium-glass laser, thulium laser , and carbon dioxide laser . Individual researchers have been considering 308-nm Excimer lamp to be used for treating Alopecia Areata by inducing apoptosis of T lymphocytes, but the effective rates had differences in studies .

Excimer laser using high-dose monochromatic UV radiation can trigger apoptosis and induce immunological suppression through altering cytokine production such as interleukin-4, interleukin-10, prostaglandin E2, platelet-activating factor, and cis-urocanic acid .

Inclusion Criteria:

• aged 16-40 years,
• Good general health,
• A clinical diagnosis of multiple Alopecia Areata of the scalp.
• Hair loss <25 percent of the total scalp.
• No use of drugs or hair care products influencing hair growth in the last 2 months.

Exclusion Criteria:

• Other causes of hair loss (like endocrine or immunological diseases).
• Skin disease in the treatment area.
• Pregnant or lactating patients.
• Hair transplantation history.
• Photosensitivity history.
• Malignant tumor history.

one year