Most of the white patches on the chest may be localized depigmentation patches formed by lichen planus. After lichen planus develops due to fungal infection, a certain inflammatory reaction occurs, and when these inflammatory reactions subside, white patches will appear on the chest, and sometimes these white patches will be accompanied by some bran-like scales. In addition to lichen planus, it may also be white pityriasis, which may also have white scales on its surface, but is not a fungal infection. In addition to this, of course, it may also be a depigmented spot caused by other reasons, such as local inflammation formed after acne, which fades to a depigmented spot. It may also be vitiligo, which is a limited white patch formed due to local melanocytes, which cannot produce melanin.