Allergy Immunotherapy: How It Works and What You Need to Know

When your body overreacts to pollen, dust, or pet dander, allergy immunotherapy, a treatment that trains your immune system to stop overreacting to harmless substances. Also known as allergy shots, it’s one of the few treatments that can actually change how your body responds to allergens—not just mask symptoms. Unlike antihistamines that give temporary relief, immunotherapy works over months or years to reduce your sensitivity. It’s not magic, but it’s science that works for millions of people with hay fever, asthma triggered by allergies, or reactions to insect stings.

There are two main types: allergy shots, injections given regularly over several years, and sublingual immunotherapy, tablets or drops placed under the tongue. Shots are more common for multiple allergens like pollen, mold, and dust mites. Tablets are usually limited to single allergens like grass or ragweed. Both work by slowly exposing you to tiny, controlled amounts of the thing you’re allergic to, so your immune system learns not to panic. It’s like training a nervous dog to sit calmly around strangers.

People who get the most benefit are those with moderate to severe symptoms that don’t respond well to meds, or those who want to avoid long-term pill use. It’s not for everyone—kids under five, people with unstable asthma, or those with severe heart conditions usually aren’t candidates. But for many, it means fewer sneezes, less nasal congestion, and sometimes even fewer asthma attacks. Studies show it can reduce symptoms by 60–80% after three to five years of treatment. And the effects? They often last for years after stopping.

You won’t see results overnight. The first phase, called buildup, takes three to six months with weekly shots. Then you move to maintenance, usually once a month for three to five years. Sublingual tablets start faster but still take months to show real change. Side effects are usually mild—a little swelling at the injection site, an itchy mouth with tablets. Serious reactions are rare but possible, which is why shots are given in a doctor’s office and you wait 30 minutes after each one.

It’s not cheap, but it can save money over time by cutting down on meds, doctor visits, and missed work or school. Insurance often covers it, especially if you’ve tried other treatments first. If you’ve been stuck in a cycle of antihistamines and nasal sprays with little relief, allergy immunotherapy might be the switch you’ve been waiting for.

Below, you’ll find real-life guides and comparisons on how this treatment fits into everyday life—from managing side effects to understanding what your allergist really means when they say "buildup phase." You’ll see what works, what doesn’t, and what most people wish they’d known before starting.