Whether or not dandruff is contagious depends on the cause, and it can be contagious if it is caused by ringworm. Dandruff can be caused by a simple increase in dandruff, or it can be caused by the presence of other diseases that cause the scalp to become infected with fungi, which then multiply and cause the cuticle of the scalp to overgrow. There are many different diseases that can cause dandruff, some common ones being seborrheic dermatitis, scalp psoriasis, eczema, and ringworm. Ringworm is caused by a fungal infection and is contagious. In addition to ringworm, seborrheic dermatitis of the head, psoriasis, eczema and other diseases are not contagious. It is recommended to go to the dermatology department of the hospital, you can do fungal microscopy, if the exclusion of fungal infection, then generally not infectious. When patients have a lot of dandruff, they can go to the hospital for examination and treatment according to the doctor’s instructions.