If youâve been living with asthma triggered by pollen, dust mites, or pet dander, youâve probably tried inhalers, antihistamines, and nasal sprays. But what if thereâs a way to change how your body reacts to these triggers-permanently? Thatâs where allergen immunotherapy comes in. Unlike medications that mask symptoms, immunotherapy trains your immune system to stop overreacting. And right now, two main options are available: allergy shots (subcutaneous immunotherapy) and SLIT tablets (sublingual immunotherapy). Both are backed by solid science, but theyâre not the same. Choosing between them isnât just about convenience-itâs about your lifestyle, your asthma severity, and what youâre willing to stick with for years.
How Allergen Immunotherapy Actually Works
Allergen immunotherapy isnât new. It started in 1911 when a British doctor injected pollen extract into a patient with hay fever. Today, we know it works by slowly exposing your body to tiny, controlled amounts of the allergens that trigger your asthma. Over time, your immune system learns not to treat them like invaders. This isnât just symptom relief-itâs disease modification. Studies show that after completing a 3- to 5-year course, many people see fewer asthma attacks, need less medication, and even stay symptom-free long after stopping treatment.
The key is specificity. Immunotherapy only works if youâre allergic to something measurable-like house dust mites, grass pollen, or cat dander. You need a skin test or blood test first. If your asthma is triggered by pollution, smoke, or exercise instead, this wonât help. And if your asthma is severe (GINA Step 4 or 5), youâre not a candidate yet. This treatment is for mild to moderate allergic asthma thatâs not fully controlled by inhalers alone.
Allergy Shots: The Classic Approach
Allergy shots, or subcutaneous immunotherapy (SCIT), involve regular injections under the skin, usually in the upper arm. The process has two phases. First, a build-up phase: you get a shot once a week for 3 to 6 months. Each shot contains a slightly higher dose of the allergen. Then comes maintenance: you switch to monthly shots for 3 to 5 years. Thatâs about 50 visits total.
Itâs not quick, and itâs not always convenient. But itâs effective. A 1999 study of 36 patients with dust mite allergies found that shots significantly improved both asthma and rhinitis symptoms. More recent real-world data from a 2024 study of over 14,000 patients showed that those on shots had fewer asthma flare-ups and needed fewer rescue inhalers over nine years. The reduction in inhaled corticosteroids was around 40%, which means less steroid exposure and lower long-term side effects.
But thereâs a catch. Every shot carries a small risk of a systemic reaction-like hives, swelling, or trouble breathing. Thatâs why shots must be given in a clinic, and you have to wait 30 minutes after each one. If you travel often, work late shifts, or have trouble keeping appointments, this can be a dealbreaker.
SLIT Tablets: The Daily Alternative
Sublingual immunotherapy (SLIT) is simpler in theory: you place a tablet under your tongue and let it dissolve. No needles. No clinic visits after the first dose. The most common SLIT tablet for asthma is ACARIZAX, approved for house dust mite allergy. Itâs taken daily, year-round, for at least three years.
Studies show SLIT tablets can reduce asthma symptoms just as well as shots-especially for people allergic to dust mites, which are a major trigger in places like Adelaide where humidity keeps mites thriving. One 2024 trial found patients using the full-dose SLIT tablet cut their daily inhaled corticosteroid use by 42%, compared to just 15% for those on placebo. Thatâs a huge difference in daily medication burden.
The biggest advantage? Convenience. After your first dose is given under medical supervision (to watch for rare reactions), you can take the tablet at home, at breakfast, before bed-any time that fits your routine. Adherence rates are higher: 75-80% of people stick with SLIT compared to 60-65% for shots. And side effects? Mostly mild: an itchy mouth or throat, which usually fades within a few weeks.
Comparing Shots and SLIT Tablets Side by Side
| Feature | Allergy Shots (SCIT) | SLIT Tablets |
|---|---|---|
| Administration | Injections in clinic | Tablet under tongue, daily at home |
| Frequency | Weekly (build-up), then monthly (maintenance) | Daily, all year |
| Total visits | ~50 over 3-5 years | 1-2 visits (initial + follow-up) |
| Time to start | 3-6 months to reach maintenance | Starts immediately after first dose |
| Best for allergens | Multiple: dust mites, pollen, mold, pet dander | Primarily dust mites (ACARIZAX), grass pollen (GRAZAX) |
| Systemic reaction risk | Higher (requires clinic monitoring) | Very low after first dose |
| Reduction in steroid use | Up to 40% | Up to 42% |
| Adherence rate | 60-65% | 75-80% |
| Cost over 3 years | Higher (clinic visits, staff time) | Lower (no visit costs after initial) |
SLIT tablets arenât perfect. You canât use them if youâre allergic to multiple allergens at once-you need one tablet for one allergen. If youâre allergic to both dust mites and grass pollen, shots might be better. Also, SLIT isnât approved for all allergens in every country. In Australia, ACARIZAX is available but not widely prescribed yet. Youâll need to see an allergist who specializes in immunotherapy to get it.
Who Should Choose Which?
Letâs say youâre a parent with a child who has asthma triggered by dust mites. You work two jobs and canât miss work for weekly appointments. SLIT tablets are the clear choice. You can give the tablet before school, no disruption.
Or youâre a 45-year-old who travels every month for work. Youâre allergic to three things: grass, trees, and dust mites. Shots can cover all three in one series. SLIT tablets? Youâd need three different products-and none are approved for tree pollen in Australia yet. Shots win here.
What if youâre scared of needles? SLIT is painless. What if you forget to take pills? Shots force you into regular contact with your doctor, which can help you stay on track. And if youâve had a bad reaction to an inhaler in the past? Immunotherapy is a different kind of treatment-no steroids, no bronchodilators. Just your immune system being retrained.
What Happens After Treatment Ends?
This is the magic part. Most asthma medications only work while youâre taking them. Stop the inhaler? Symptoms come back. Stop SLIT or shots? Many people stay better. A 2024 study of nearly 3,000 patients found that even after stopping immunotherapy, they had 20% fewer lower respiratory infections needing antibiotics. Thatâs not just less asthma-itâs fewer colds, fewer bronchitis episodes, fewer trips to the doctor.
And for kids? The evidence is even stronger. Nine out of ten studies show that children with allergic rhinitis who get immunotherapy are far less likely to develop asthma later. Thatâs prevention, not just treatment. If you have a child with seasonal allergies, starting immunotherapy early could change their health trajectory.
Barriers and Real-World Challenges
Itâs not all smooth sailing. First, cost. In Australia, SLIT tablets arenât fully subsidized. Youâll pay out-of-pocket-around $150-$200 per month. Shots are partially covered under Medicare, but you still pay for each visit. Insurance coverage varies widely.
Second, access. Only a handful of allergists in Adelaide offer SLIT tablets. Most clinics still default to shots because theyâve been around longer. You might need to travel or wait months for an appointment.
Third, patience. Neither option works fast. You wonât feel better in a week. It takes 6-12 months to notice a difference. Most people quit before the 2-year mark because they donât see immediate results. But if you stick with it, the payoff is real: fewer inhalers, fewer attacks, and a life less controlled by allergies.
The Bottom Line
Allergen immunotherapy is the only treatment for allergic asthma that can change the course of the disease. Shots and SLIT tablets both work. The difference is in how you live.
Choose shots if: youâre allergic to multiple allergens, you can commit to clinic visits, and you want the broadest allergen coverage.
Choose SLIT tablets if: youâre allergic to dust mites or grass pollen, you want to avoid needles, you value daily convenience, and youâre good at sticking to a routine.
Neither is right for everyone. But if your asthma is tied to allergies-and youâre tired of just managing symptoms-itâs time to consider a cure that doesnât come in a puff.
Can SLIT tablets treat asthma caused by pet dander?
Currently, no SLIT tablets are approved in Australia for pet dander allergies. Only dust mite (ACARIZAX) and grass pollen (GRAZAX) tablets are available. For pet allergies, allergy shots are still the only form of immunotherapy that can include animal dander allergens in the mix.
How long until I feel better with allergy shots or SLIT?
Most people start noticing fewer symptoms after 6 to 12 months. The full benefit usually takes 2 to 3 years. Donât expect instant relief. This is a long-term training program for your immune system, not a quick fix.
Are SLIT tablets safe for children?
Yes, SLIT tablets are approved for children as young as 5 years old in Australia for dust mite allergy. Theyâre often preferred for kids because theyâre needle-free and easier to manage at home. Studies show they reduce asthma attacks and the need for rescue inhalers in children with allergic rhinitis.
Can I take SLIT tablets while using asthma inhalers?
Absolutely. SLIT tablets are designed to be used alongside asthma medications. In fact, many patients start SLIT while still using inhalers. Over time, as your immune system adjusts, your doctor may reduce your inhaler dose-sometimes by as much as 40%.
What if I miss a day of SLIT tablets?
Missing one day isnât a big deal. Just take the next dose as scheduled. Donât double up. If you miss more than 7 days in a row, contact your allergist. You might need to restart at a lower dose to avoid reactions. Consistency matters, but perfection isnât required.
Is immunotherapy covered by Medicare in Australia?
Allergy shots are partially covered under Medicare if prescribed by a specialist. SLIT tablets are not currently subsidized, so you pay the full cost-around $150-$200 per month. Some private health insurers offer partial rebates for immunotherapy under extras cover. Always check with your provider.
Next Steps if Youâre Considering Immunotherapy
Start with an allergy test. See an allergist who can do skin prick tests or specific IgE blood tests to confirm whatâs triggering your asthma. If itâs dust mites, grass, or tree pollen, immunotherapy is worth exploring.
Ask your allergist: âDo you offer SLIT tablets? If not, why?â If they donât, ask for a referral to a specialist who does. Bring up the 2024 Asperti study showing 42% steroid reduction-itâs now standard evidence in European guidelines and gaining traction here.
Track your symptoms for a month before starting. Note how often you use your rescue inhaler, how many nights you wake up coughing, how many days you miss work or school. After 12 months on immunotherapy, compare the numbers. You might be surprised how much better you feel.
Samar Khan
December 29, 2025 at 00:18
OMG I tried SLIT for dust mites and it was a GAME CHANGER 𼚠I used to wake up gasping 3x a week-now I sleep like a baby. Also, no more $80 inhalers every month. My cat still hates me but at least I can breathe when I hug him đđ