Be aware that herpes virus tends to thrive in an environment rich in the amino acid arginine. A diet with a high lysine to arginine ratio can keep herpes at bay and help to heal those cold sores sooner.
High arginine foods to avoid or eat in moderation with balancing high lysine foods (or a lysine supplement, if necessary): nuts and nut butters, sesame seeds and tahini, chocolate, winter squash, orange and grape juices, pea protein powder, coconut, oatmeal.
High Lysine foods: raw dairy products (if allowable for your child), avocado, meats, fish (stick to low mercury varieties no more than once a week). Some fruits and vegetables with a higher lysine to arginine ratio are papaya, beets, mango, apples, apricot, pears, figs, tomato, turnips, but keep in mind that the total lysine available in most fruits and vegetables is relatively small compared to the amount in meat and dairy products.
For a comprehensive listing of lysine to arginine balance in foods, click here.