There are many reasons why there is no tongue coating at the back of the tongue, such as congenital factors, ringworm of the tongue, atrophic lingual inflammation and so on. 1. Congenital factors: the lack of tongue coating at the back of the tongue may belong to congenital factors, in addition to the phenomenon will not be accompanied by other symptoms, without special treatment. 2. Ringworm: lack of vitamins and trace elements in the body can induce ringworm, which leads to the phenomenon of no tongue coating behind the tongue. 3. Atrophic lingual inflammation: atrophic lingual inflammation also leads to the absence of tongue coating at the back of the tongue. There are many factors for this disease, such as improper diet, endocrine disorders, fungal infections, blood diseases, etc., which may induce this disease, thus resulting in the appearance of the absence of tongue coating at the back of the tongue. There are many other reasons why there is no tongue coating on the back of the tongue, if we exclude congenital factors, we suggest that patients go to the hospital in time to improve the examination, clear diagnosis and take standardized treatment according to the doctor’s instructions, and do not ignore the symptoms and take it lightly.