White hairy patches in the mouth may be hairy leukoplakia or white hairy tongue, as follows. 1. Hairy leukoplakia: it is a sign of severe suppression of systemic immunity of patients, which can be seen in HIV-infected patients, bone marrow or patients after organ transplantation, manifested as white or grayish white patches on both sides of the tongue margins, presenting the appearance of vertical folds, such as overgrowth can be furry and can not be wiped off. 2. White hairy tongue: it is the hairy damage formed by excessive prolongation and delayed shedding of filiform papillae at the dorsum of the tongue, which occurs in the middle of the anterior 2/3 of the dorsum of the tongue, and the length of the hairs can be from a few millimeters to more than one centimeter, and there are often food residues remaining on the surface. There may be other reasons for the appearance of white hair spots in the oral cavity, it is recommended to go to the hospital in time, clear causes for targeted treatment.