Large dandruff on the scalp may be caused by improper cleaning, excessive scratching and other physiological factors, or consider seborrheic dermatitis, head simple furfuraceous rash and other diseases. 1. Physiological factors: If the hair is not cleaned properly, excessive scratching of the scalp may lead to excessive sebum secretion, appearing scalp long large dandruff situation. If such a situation, do not worry, is a normal phenomenon. 2. Seborrheic dermatitis: Seborrheic dermatitis may be caused by heredity, dietary disorders, neurological dysfunction, immune dysfunction and other factors. Patients will appear in the scalp chaff-like dandruff, and accompanied by vesicles, oozing, itching and other symptoms, manifested in the scalp long large dandruff. 3. Head simplex furfura: the cause of head simplex furfura is not yet completely clear, may be excessive sebum secretion, Malassezia infection, heredity and other factors. The patient manifests as bran-like or powdery dry scales on the scalp, and there may be a situation where the scalp grows large dandruff. There are many reasons for large dandruff on the scalp, patients can go to the regular hospital, relevant examination, so as to identify the cause of the disease.