Lichen planus includes many types of skin diseases that share the common characteristic of lichenoid changes. These diseases are difficult to cure, easy to recur, and have a relatively long history. The causes of lichen planus are many and complex, specifically they should be related to neuropsychiatric factors, gastrointestinal dysfunction, endocrine disorders, and dietary, environmental, and genetic factors. Try not to scratch the rash during the whole process of development. Patients should usually maintain a calm state of mind, eat a light diet, try not to rub the rash area with a bath towel when bathing, and use alkaline toiletries as little as possible.