Simply because you’re both right.

One is correct in that repeated exposure to an allergen can upregulate IgE production, especially in cases of severe allergies like bee stings or peanuts. This is due to the immune system's sensitization process, where each exposure can lead to more intense reactions, driven by the Th2-mediated immune response that promotes IgE production and allergic inflammation.

However, one is also correct that controlled exposure through allergen immunotherapy (SCIT or SLIT) can downregulate IgE and mitigate allergic responses. This therapy works by gradually introducing the allergen in controlled doses, which shifts the immune response from a Th2-dominated profile to a Th1-dominated or regulatory T cell (Treg) profile. This shift reduces IgE levels and increases the production of blocking antibodies like IgG4, leading to long-term desensitization and reduced allergic reactions.

In particular environmental allergens (pollens, dust mites, animal dander, molds), insect venoms (bee, wasp) may respond well to immunotherapy but we’ve had poor success or disproportionate risk attempting to mitigate food allergens (peanuts, tree nuts, and shellfish), certain medications, and latex .

You're training a different kind of immune sensitivity. You're still inducing inflammation, and you're still allergic, you just see less IgE response.