The condition of 4-month-old baby with white spots on forehead may be due to white furfur rash, lichen planus, vitiligo and other factors, which can be chosen for temporary observation, medication and so on. 1. white chaff rash: this is a skin disease of unknown etiology, it occurs on the face, preferably in children, it can subside on its own, usually does not need special treatment, but avoid excessive cleaning. 2. lichen planus: also known as lichen planus chafing, mainly due to malassezia invasion of the skin keratin and caused by fungal skin infections, there will be a spotty rash, and gradually develop into a flaky surface with scales, so there will be forehead white spots, you can choose clotrimazole, econazole, miconazole, and other antifungal ointment treatment. 3. Vitiligo: this is a disease caused by melanocyte destruction of the skin, can occur in any part of the body, so there will be forehead white spots, you can choose to tacrolimus cream, carbotenoids ointment and other smear treatment. 4 months baby forehead with white spots may also exist other causes, so we must cooperate with the doctor to improve the examination, and then give the appropriate drug treatment, not blindly use drugs.