Can hyperpigmentation after excimer treatment for vitiligo be reduced?

It may help reduce excessive melanin production and oxidative stress caused by ultraviolet radiation.

The three ingredients each work in different ways.

Vitamin C (L-ascorbic acid) inhibits the activity of tyrosinase, an enzyme involved in melanin synthesis, thereby reducing melanin production and helping to reduce already-formed oxidized melanin.

Vitamin E (tocopherol) is a fat-soluble antioxidant that prevents lipid peroxidation of cell membranes. When used with vitamin C, they can complement each other's antioxidant actions.

Adding ferulic acid increases the stability of vitamin C and enhances its antioxidant effect.

A study has reported that combining 15% vitamin C, 1% vitamin E, and 0.5% ferulic acid significantly increased the skin's protective effect against ultraviolet radiation.

In other words, using the three ingredients together can be expected to reduce pigment that is excessively produced by ultraviolet radiation while also helping to control oxidative stress in the skin.

In the 4 patients observed by our research team, hyperpigmentation improved while repigmentation was maintained.

The study involved 4 patients with facial vitiligo who developed hyperpigmentation while using excimer laser and tacrolimus 0.1% ointment.

They were instructed to use a vitamin C, E, and ferulic acid serum twice a day, and monthly VISIA imaging was used to observe repigmentation of vitiligo and changes in hyperpigmentation.

In a 42-year-old female patient, both vitiligo and hyperpigmentation markedly improved at 1 month and 3 months after adding the serum.

In a 52-year-old male patient, hyperpigmentation decreased at 1 month with some recurrence of vitiligo, but with continued treatment, vitiligo improved again and hyperpigmentation also significantly decreased by 3 months.

Overall, all 4 patients achieved F-VASI90, meaning repigmentation in 90% or more of facial vitiligo, while hyperpigmentation also decreased.

These results should be considered as a study involving a small number of patients, but they are meaningful in showing the potential of adjunctive care to reduce hyperpigmentation that occurs during excimer treatment.

In this study, the vitamin C, E, and ferulic acid serum was not observed to interfere with repigmentation of vitiligo.

When vitiligo patients hear about using skin-lightening ingredients, the first concern is whether the pigment that was difficult to restore might fade again.

However, all patients in the study achieved 90% or more facial repigmentation while using the serum.

In other words, at least in this study, using the serum reduced hyperpigmentation while maintaining the repigmentation effect induced by excimer laser.

The action of vitamin C is also closer to regulating overactivated melanin production rather than destroying melanocytes.

In contrast, repigmentation by excimer laser proceeds as melanocytes remaining in hair follicles are activated and migrate.

Therefore, in these observations, we could confirm the possibility of reducing excessive hyperpigmentation while maintaining normal repigmentation of vitiligo.

It is important to check the concentration and storage conditions, and to use it while monitoring for skin irritation.

Vitamin C in the form of L-ascorbic acid is easily oxidized when exposed to light and air.

Therefore, refrigeration after opening is recommended, and if the product has turned dark brown, oxidation may have progressed considerably, so it is advisable to avoid using it.

Concentration is also important.

If the vitamin C concentration is less than 8%, sufficient effect is difficult to expect, and if it exceeds 20%, skin irritation may increase rather than the effect increasing further, so a product of about 10–20% is appropriate.

The product used in this study also falls within this range.

Also, because L-ascorbic acid products have a low pH, they may feel stinging or irritating when first used on sensitive skin. It is recommended to start with a small amount and adjust the quantity while checking your skin's reaction.

Above all, if hyperpigmentation occurs during vitiligo treatment, we do not recommend arbitrarily adding various skin-lightening products.

It is advisable to first check the current treatment stage and degree of repigmentation of vitiligo, and then discuss with your dermatologist whether additional management is needed.

Hyperpigmentation that occurs during excimer treatment for vitiligo does not mean that the treatment is going wrong.

Rather, it can appear as melanocytes respond to ultraviolet light, and in most cases, it may fade over time.

However, if facial hyperpigmentation makes it difficult to continue treatment, adjunctive management that maintains repigmentation while controlling only excessive pigmentation can be considered together.