A rough patch of skin is usually caused by physical friction, chronic inflammatory dermatosis, dermatophytosis and other reasons. 1. Physical friction: As the local skin is stimulated by friction for a long time, it may lead to local skin hyperplasia, and the friction area becomes rough, but there is no other abnormal symptom, which will be gradually recovered after avoiding repeated friction. 2. Chronic inflammatory skin diseases: If you suffer from chronic eczema, chronic contact dermatitis and other skin diseases, under the stimulation of inflammation, it can lead to local skin hyperplasia, keratinization, hypertrophy and even cracking, so there is a piece of rough skin phenomenon. 3. skin ringworm disease: if you suffer from ringworm, ringworm, tinea, tinea pedis and other skin ringworm disease, will lead to local skin erythema, papules, blisters and other symptoms, in the development of the disease can also appear flaking, which leads to a piece of rough skin. After excluding the cause of physical friction, you should go to the hospital in time and ask the doctor to check and treat it.