I have an 8 month old baby that breaks out in a rash every time he eats. Anyone know why that may be.?

May be food allergy. It's probably a good idea to talk with your pediatrician about this. Your baby might have a food allergy. It could be related to the type of milk he is drinking or it could be specific foods. Occasionally doing some limited food allergy testing may be helpful to determine the cause if a food elimination diet trial (or change in milk if he is on formula) does not solve the problem.
Food allergy. "everytime he eats" suggests an allergic reaction to something eaten at every meal. At 8 months that would be breast milk or formula. If your child is taking a cow's milk based formula try switching to a soy formula, alimentum or nutramigen for 4-6 days. Foods that you eat commonly enter the breast milk - not "leaky gut" but a universal phenomenon. Dr. Roberts is right - talk to the pediatrician.
Consult. At eight months the diet should be starting to vary with baby foods in addition to formulas. Rash everytime he eats is curious. Is the baby very fussy at meal times? Does he also get rashes at other times when he is not eating? You need to consider mastocytosis which is generally benign when developed in infancy. Either way, as always best to consult pediatrician and let her watch baby feed.
Food allergy. I agree, sounds like something that is ingested at every meal. At that age it's usually formula or a cereal (oatmeal or barley in some cases. You can start a "food journal" to record everything he eats, then talk to your pediatrician.