Thumb depression, the common clinical causes are mainly the following: First, the patient’s thumb after trauma, the body in the process of repairing the deformity healing, can be manifested as a local depression, but does not affect the normal physiological function of the patient, can not be special treatment, close observation can be. Second, patients due to malnutrition, lack of vitamins or trace elements in the body can cause nail depression, and accompanied by pale color. Patients need to eat more fresh vegetables, fruits, eggs, milk, etc., strengthen exercise, improve the immunity of the body, some patients can gradually improve the symptoms of thumb depression. Third, patients with fungal infections at the thumb can cause gray nails, which are manifested as depressions of the big toe. Patients need to go to the dermatology department as soon as possible, give drugs such as fluconazole and other antifungal treatment, keep the nails clean, some patients can achieve certain treatment results.