1 Some babies are so sensitive to these foods that if the offending food is eaten by the mother, drinking her breast milk can cause a reaction. 2  Most children outgrow allergies to eggs, milk, wheat, and soy. 3  Peanuts, tree nuts, fish, and shellfish cause most of the allergic reactions in teens and adults.
Side effects can include skin discoloration and irritation. Long-term use, especially of stronger prescription corticosteroids, can cause thinning of the skin and disruption of normal hormone levels. Examples include: 1  Betamethasone (Dermabet, Diprolene, others). 2  Desonide (Desonate, DesOwen). 3  Hydrocortisone (Cortaid, MiCort-HC, others). 4  Mometasone (Elocon).
Although the exact details of how allergy shots work is unknown, we do know the general way they affect the immune system. An allergic reaction occurs when the body is exposed to an external substance (the antigen) that the immune system interprets as a foreign invader.