answer:You are right about allergy shots. You are sort of right about allergies, but mostly exposure to allergens decreases the chances of allergy. For example, children who live in households with pets are less likely to develop asthma. Children who live in households with normal amounts of dust and dirt are less likely to develop allergies to dust. What can happen is that once having been exposed to an allergen, the allergic reaction can get worse over time. For example, I am allergic to bee stings. I was not allergic to them as a child. The allergy developed when I was in my 20s. The last time I was stung by a bee on the back of my hand, my arm got red and swelled up to my elbow. I have been told I should get an epi pen.