Why Is 308 Excimer Laser Treatment Effective in Some Parts But Not in Others of Vitiligo?

There are individual differences in excimer laser treatment of vitiligo. Related to the following factors:

①Skin color (skin type)

②Skin lesion time (generally, the recovery time is quicker if the onset time is short)

③Skin lesion location ( it has the best treatment effect for head, face, and trunk, followed by the limbs. And the back of the fingers, palms, and soles are of poorer effect than that of head,so more times are needed)

When excimer laser is used in the treatment of psoriasis, there is little individual difference, but there are also slight differences in the location of skin lesions (the head, face and trunk are better than the limbs)

What Is the Reason for the Difference?

The direct cause of the formation of vitiligo vulgaris is the death of melanocytes in the white patches due to the immune killing of T lymphocytes. In vitiligo, T cells recognize and kill melanocytes specifically. There are primitive melanocytes in human hair follicles. They do not express the characteristic markers of melanocytes, so they can generally escape the killing of T cells.

The recovery of vitiligo requires excimer laser to stimulate these remaining primitive melanocytes to grow into functional mature melanocytes to make the white patches recover, this is why small islands of pigment often appear around the sweat pores first during the recovery of vitiligo, and then the small islands expand and finally recover.

The reason why different parts of the body respond differently to treatment is related to the distribution density of hair follicles in different parts of the human body, the type of hair follicles, and the blood supply of the skin there. The palms and soles of the feet do not have hair follicle, therefore they are the most difficult to treat.