Sweating is necessary to control body temperature, it is a way of cooling the body in warm'hot situations. Excessive sweating (hyperhidrosis) of the scalp can be embarrassing. Primary hyperhidrosis starts earlier in life and the secondary type is usually due to an underlying problem. It can be due to a thyroid or pituitary gland problem, diabetes or tumors. If it is that severe and is embarrassing to you and interrupting your lifestyle, then I recommend evaluation by your physician. There are medications that can be prescribed. In the meantime, avoid standing in the sun, drink plenty of water, use a handkerchief, to wipe away sweat, use antiperspirant, and avoid spicy foods.