What is it?

The Excimer laser is FDA-cleared for the treatment of psoriasis, atopic dermatitis (eczema) and vitiligo (pigment loss thought to be due to a systemic autoimmune disorder). The Skin Specialist Centre has now introduced the Xtrac Excimer laser from PhotoMedex for improvement of the above conditions. We are the first and the only centre to introduce this device to New Zealand and the current model is the most updated model in Australasia. The laser also treats white scars, laser-induced hypopigmentation and hypopigmentation induced by trauma and medical procedures. The Excimer laser has shown efficacy in managing granuloma annulare, prurigo nodularis, genital lichen sclerosus and alopecia areata (although it is not FDA-cleared for these uses).

XTRAC Excimer Laser

Mechanism of Action

The laser induces breakage of DNA strands and increases expression of mitochondrial apoptotic proteins in T cells. This action has been proposed as the basis for the decreased epidermal proliferation index and clinical remission observed in psoriasis.

In vitiligo, the laser would appear to stimulate melanocyte proliferation and migration of reservoir melanocytes to the epidermis from the outer sheath of hair follicles. It is also proposed that its immunosuppressive and immunomodulatory action stabilizes the disease.

Who Should Consider Excimer Laser Treatment?

The laser is used in managing localised hand and feet psoriasis (palmoplantar psoriasis) and plaque psoriasis with less than 10% body surface area involvement. It is also useful in treating non-exposed sites such as the scalp, ears, axillae and groin. It has successfully treated hard-to-treat areas including the elbows, knees, lower legs and ankles.

In the treatment of vitiligo, the face responds best, along with the neck, armpits and trunk. Digits, feet and hands and other bony prominences are the most difficult to treat.

In atopic dermatitis, it has been used to treat eczema involving the arms, legs, face and trunk.


  • Avoids messy creams and daily skin care regime.

  • Sessions only last a few minutes

  • Effective clearing, often in as few as four sessions

  • Provides long-lasting relief, typically several months free of symptoms.

  • There is no direct UV light exposure to healthy skin

  • Virtually painless

How Does it Work?

The Excimser laser creates a concentrated but painless beam of ultraviolet light that is delivered to the involved treated areas through a handpiece that rests directly on the skin. By precisely targeting only active lesions, without exposing healthy skin, the laser safely delivers high dose treatments, for fast clearing and longer remission.

On the first visit, your skin is tested to determine the optimum dosage of light appropriate for your condition. At the second treatment, the Xtrac handpiece is moved across the involved area, applying laser light at the previously determined dose. Depending on the area to be treated, this typically takes a few minutes


Excimer last treatment does not require anaesthesia, as the procedure causes minimal, if any, immediate discomfort.

Side Effects

The most common side-effect is mild to moderate redness in the treated sites.

Post-Procedure Care

Emollients may be prescribed for dryness, if it occurs. A sunscreen (minimum SPF50) is recommended.

Treatment Regime and Treatment Endpoint


The frequency of treatment is typically two to three times weekly, with over 90% improvement in an average of ten sessions. It is essential that there is a minimum of 48 hours between treatments, which are tailored to each lesion. Comparative studies have shown that the Excimer laser consistently produces better results than narrow beam-UVB (light box). On average, the remission time with Excimer laser therapy ranges from three to six months.


Ideally, the treatment frequency should be three times weekly, but it can be twice weekly. At least eighteen treatments are required, by which time there should be the development of repigmentation, although ideally thirty-six treatments are required. Studies comparing Excimer laser with narrow beam-UVB (light box) therapies have found a higher induction of repigmentation with the Excimer laser. Also, with this laser, fewer treatment sessions are required. It significantly reduces the lower amount of light required for repigmentation. Also, Excimer repigmentation is more rapid than narrow beam-UVB light therapy.

Atopic Dermatitis:

In atopic dermatitis, the number of sessions should ideally be twice a week, with the number of sessions varying from six to twelve, with most patients maintaining clinical results at a four month follow-up.