The red spots on the back of the neck of newborns may be caused by nevus erythematosus, or localized eczema or atopic dermatitis. 1. nevus erythematosus: if the red spot on the back of the newborn’s neck is not itchy and does not have other symptoms, then it may be nevus erythematosus, which is caused by capillary dilatation due to embryonic dysplasia, and can be considered to be treated with laser. 2. Pathological: if accompanied by itching and other symptoms, it may be suffering from localized eczema or allergic dermatitis and other skin diseases, mostly caused by inattention to skin cleaning or contact with allergens. If newborns have red spots on the back of their necks, it is recommended that they go to the hospital in time to receive responsive treatment after diagnosis.