Introduction to laser treatment of vitiligo

Vitiligo or leukoderma is a chronic skin pigmentation disorder that causes white irregular patches on the skin in different parts of the body. It is caused by the destruction of pigment producing melanocytes cells of the skin. The hair on vitiligo-affected skin also sometimes turns white. Vitilogo treatment is necessary since it can have a damaging psychological impact on patients.

Traditionally, vitiligo has been treated by topical steroids and phototherapy, for both local and genaralized vitiligo. However, results were not satisfactory. The pigment selective 308nm excimer laser promises to improve on existing traditional therapies.

Laser treatment can be either monotherapy or combined therapy.

Monotherapy with lasers for vitiligo

A series of studies have shown the ability and effectiveness of 308nm excimer laser to repigment the skin. Using appropriate low fluences and one to three sessions per week for one to six months, these studies gave outstanding results, repigmenting 57% to 100% white patches. However, evaluation must also consider the extent of repigmentation of every patch. 75% repigmentaion is considered satisfactory. In one series, 20 to 30% patches attained this level of repigmentation. Another series of studies gave conflicting results.

Of the several factors, which determine the rate and extent of repigmentation of depigmented skin patches, the loclization of the lesions seems to play a critical role. The extent of repigmentation, it seems, is influenced by localization of the lesions. One study reported 75% repigmentaion on all facial patches but none on the hands and feet. The conflicting results in other studies indicate that localization certainly plays a role in repigmentation.

The frequency of laser treatments can be once, twice or three times a week. The rate of repigmentation appears to be linked to the total number of sessions and not to the frequency of sessions. It is difficult to know the stability of the repigmentaion with time, since the follow up studies were either too short to be of any value or there were none. A recent study found no depigmentaion at the end of one year of treatment. According to other studies, about 15% of new depigmentation was observed one to three years after the end of treatment.

However, tolerance shown by patients to treatments was usually very good. The immediate side effects were restricted to erythema and rare blister lesions.

Combined therapy with lasers for vitiligo

The treatment of vitiligo lesions by the topical 0.1% tacrrolimus medication showed good results. However, best results were obtained when exposure to the sun accompanied treatment by topical tacrolimus. As a resullt, two pilot prospective studies were done to evaluate the combined therapy of 308nm excimer laser and 0.1% tacrolimus ointment.

These studies compared the efficacy of the combined therapy of excimer laser and tacrolimus ointment with excimer laser monotherapy or laser combined with a placebo. In the first therapy, two sessins were performed in a week and in the second treatment three sessions per week. In both therapies, 24 sessions were performed and 0.1% tacrolimus was applied twice daily. On comparing the rsesults, the combined therapy clearly stood out as superior in terms of efficacy and short response time. Tolerance was good and the immediate side effects were restricted to constant erythema and rare bullous or itching lesions. However, since these results were obtained from a small population any action must await confirmation from studies on larger populations.

The use of systemic tacolimus in organ transplant patients exposes them to an increased risk of cutaneous cancer. Therefore, for safety reasons, UV exposure is restricted in local treatments with topical tacrolimus, though, it must be stressed, the barrier function of the vitiligo skin remains normal. However, the restricted UV exposure results in poor penetration of the tacrolimus ointment into the interfollicular epidermis, affecting treatment response. Restricting tacrolimus use has another disadvantage as demonstrated in studies on mouse, where the tacrolimus was seen to protect against any UV induced DNA damage. However, since long-term follow up studies are lacking and the risk of cancer cannot be completely eliminated, the use of this combined therapy of excimer laser and tacrolimus should, for the present, be restricted to controlled studies.

The combination therapy of excimer laser and topical steroids lacks proper evaluation. In the experience of some, combination of 308 nm excimer laser and one daily application of a class II topical steroid have the potential to be a superior treatment to laser monotherapy and nearly match the results obtained in the combined therapy of excimer laser and topical tacrolimus. If these results are confirmed, then the combined excimer laser- topical steroid therapy would represent a significant advance over other treatments, since there would be no risk of cancerous conditions developing.