Are allergic to goat's milk in the adult possible?

Earlier allergic reaction of his body did not observe any food nor med.preparaty.But it is not clear for what reasons the start itching all over the body and head( !).Feelings of trouble.Particularly intensified in the second half of the night.New drugs are not taken, the products have not tried, except goat milk a few cups a day.Goat milk before never saw, even in childhood.Spots on the skin there, but appears occasionally itchy.Everywhere write that goat's milk on the contrary is prescribed for people with severe allergies, since it acts treatment and improves the immune system.