I went through the series of allergy shots for 5 years from the ages of 14 to 19. Did it help? I don't think there is any real answer for that. Age sometimes factors into allergy severity. Also during some of this time I lived about 200 miles from where I grew up. I do not believe the shots helped at all with my allergy to raw fruits and vegetables, nor was the intention. The shots were to build up a tolerance to the other things I was allergic to.
Over the years, I was able to tolerate eating a salad or eating veggies if I coated them with dip (I tried to trick my body, which of course didn't work). The dip seemed to soothe the reactions just a little. I would eat these foods because I loved them and also because of the nutritional value. I would have a little discomfort for a while, but usually nothing visible. In fact, most people whom I've known for years don't know I have this allergy or forget unless I remind them.
The technical/medical term for this allergy is Oral Allergy Syndrome. It occurs when there is cross reactions between foods and pollen from weeds, trees, etc. For example, since I have such an allergic reaction (sneezing, wheezing, etc) to birch trees then certain fruits and vegetables may have pollens associated with birch trees causing a reaction. Reactions can vary from food to food and from person to person. Typically for me it's just an big lump in my throat for about a half hour. It may be longer depending on the food and how much I eat. My throat feels swollen and hurts. Sometimes I'll sneeze and apples sometimes make my lips swell up. Nothing serious, but makes the enjoyment of eating disappear. I normally eat small portions because the reaction can occur so quickly.
When I was 29 years old I had been able to build up a pretty good tolerance to most raw fruits and vegetables, and I pretty much knew which ones were going to cause more discomfort than others. Then I got pregnant. And you won't believe this. But I was able to eat everything that I was allergic to -- apples, bananas cucumbers, my favorite carrots, etc. Oh, it was fantastic. I didn't even realize it. Since I had been slowly buildng up that tolerance I just bought more fruits and vegetables when I was pregnant. I ate them without thinking -- maybe I had something more important on my mind. It was the best part of the pregnancy.
About a month after my daughter was born, I reached for a carrot at dinner without thinking. Ate it up and my throat hurt worse than it ever had hurt. It hurt all night and I even felt it a little the next morning. What?? But I could eat it all and it was so good. On Christmas, I ate a raw almond and almost went into anaphylaxis shock. I was almost gagging for air. I quickly found some benadryl (I was still nursing and not on any other allergy medicine) and it got better quickly. What?? I used to eat those even before the pregnancy with very little to no reaction. Did my body allow me to get the wonderful benefits of fruits and vegetables for the sake of my unborn child? Is that possible? That is my conclusion.
So, now I am slowly trying fruits and vegetables again. And I ate cucumbers this summer and an avocado last week. You have no idea how exciting it is to eat something that normally makes you uncomfortable. I hate, absolutely hate, when I hear people moan and groan about eating fruits and vegetables to stay healthy. I would love to taste the sweet flavors of fruit every day if I could. Next week we are hitting the apple orchard. And no matter how much my throat hurts, I'm eating those tasty apples. Or at least until my lips swell up and I start sneezing.
I knew my daughter would have some kind of allergies. I didn't think she would develop them at 6 months or to milk products. I asked one allergy doctor (we've been to three now for her) about her developing the Oral Allergy Syndrome and he told us that it's not a life threatening allergy. And not to worry if she does have it. I guess I have to wait for her to tell me. Right now she's eating lots of raw fruits and I watch to see if she reacts differently. Raw vegetables are harder to give to a 2-year-old, but in time we will see. For now, we worry about milk, eggs, peanuts and cashews.