Desensitization and Immunotherapy for Dogs – Pros and Cons

About 10–15% of dogs are thought to live with atopic dermatitis – an allergic skin disease driven mostly by environmental allergens like dust mites and pollens. Of those who go on allergen‑specific immunotherapy (ASIT), roughly 60% will get at least a 50% improvement in their symptoms. That’s not a miracle cure rate, but it’s also not nothing – especially when the alternative is years of itching, infections, and repeat steroid courses.

This is the strange middle ground of “allergy shots” for dogs: not guaranteed, not quick, but often the only treatment that tries to change the disease itself rather than just quiet it down.

This article is about that middle ground – what desensitization and immunotherapy can realistically do, what they can’t, and what it feels like to live through the process with a real dog, not a textbook example.

What “desensitization” and “immunotherapy” actually mean

You’ll hear a lot of terms. They sound technical because they are, but they describe a fairly intuitive idea: teaching the immune system to overreact less.

Key terms in plain language

• Allergen-specific immunotherapy (ASIT): A long‑term treatment where your dog is given tiny, controlled doses of the exact allergens they’re sensitive to (dust mites, certain pollens, molds, etc.). The dose is slowly increased over time to train the immune system to tolerate them.

  
  

• Desensitization: The overall process of reducing allergic reactivity through repeated exposure in a controlled way. ASIT is the main way we do this in dogs.

  
  

• SCIT (Subcutaneous Immunotherapy): “Classic” allergy shots: allergen extract is injected under the skin.

  
  

• SLIT (Sublingual Immunotherapy): Allergen drops or spray given under the tongue, usually at home.

  
  

• ILIT (Intralymphatic Immunotherapy): A newer approach where allergen is injected directly into a lymph node – the immune system’s command center. Fewer injections, potentially faster effect, but usually only available in specialist settings.

Under the hood, all of these are trying to steer the immune system away from an allergic pattern and toward tolerance.

How immunotherapy changes the immune system (and why that takes time)

Allergic dogs have immune systems that lean heavily toward a “Th2” pattern – a type of helper T cell response that promotes IgE production and allergic inflammation.

ASIT aims to:

• Dial down the allergy machinery

  • Reduce activity of mast cells and eosinophils (cells that release histamine and other itch‑inducing chemicals).

  • Decrease allergen‑specific IgE over time, or at least make it less central to the reaction.

    
    

• Strengthen the “brakes” of the immune system

  • Increase regulatory T cells (Treg cells), which act like peacekeepers, calming inflammation.

  • Boost anti‑inflammatory signaling molecules (like IL‑10 and TGF‑β).

    
    

• Shift the balance of response

  • Push from a Th2‑dominant (allergic) pattern toward a more Th1‑dominant and regulatory pattern.

  • Increase certain IgG antibodies (in humans, IgG4 is a “blocking” antibody that can intercept allergens before they trigger IgE; in dogs, similar patterns are suspected but not fully mapped out yet).

    
    

In humans, these changes are well documented. In dogs, the immune shifts look broadly similar in smaller studies, but the details – especially which antibody subtypes matter most – are still being worked out.

What this means for you: Immunotherapy isn’t like giving a painkiller and watching the itching ease in an hour. You’re trying to gently remodel how the immune system reacts. That’s months, not days.

How well does immunotherapy work in dogs?

There’s no way to sugarcoat the variability: some dogs do brilliantly, some improve but still need other medications, and some don’t respond at all.

The big picture numbers

Across studies and reviews:

• Around 60% of dogs with atopic dermatitis on ASIT achieve a clinically meaningful improvement (often defined as >50% reduction in symptoms or medication needs).[1][2][5]

A large retrospective study of 664 dogs on subcutaneous immunotherapy found:[1]

• 31.5% – Excellent response

  ASIT alone controlled the signs of allergy.

  
  

• 28.5% – Good response

  More than 50% improvement; still needed some additional treatments.

  
  

• 40.1% – Poor response

  Less than 50% improvement.

  
  

So roughly:

• 3 in 10 dogs do very well.

• 3 in 10 dogs improve meaningfully but still need help.

• 4 in 10 see only modest or minimal benefit.

That’s the uncomfortable truth – and also the reason expectations matter so much.

Owner perception vs. clinical scores

Interesting twist: in some studies, owners rated their dogs’ improvement higher than the formal lesion or itch scores suggested.[2]

Two reasons this might be true:

1. Small changes feel big in daily life.Going from “awake half the night scratching” to “scratches a few times then settles” is a huge quality‑of‑life shift, even if the skin isn’t perfect.

   
   

2. Reduced reliance on steroids or other heavy medications often feels like a win in itself, even if the skin isn’t totally clear.

Your lived experience with your dog matters as much as the numbers on a scoring sheet.

Different types of immunotherapy: SCIT, SLIT, ILIT

Right now, most dogs receive SCIT or SLIT. ILIT is emerging and promising but not widely available.

Quick comparison

Approach	How it’s given	Typical setting	What the research suggests
SCIT (subcutaneous injections)	Injections under the skin, often at home after initial training	General practice or dermatologist	The most studied method. Around 60% of dogs show ≥50% improvement; good safety when used correctly.[1][2][5]
SLIT (sublingual)	Drops or spray under the tongue, usually daily	Often prescribed by dermatologists	Early data suggest lower efficacy than SCIT in some reports (e.g., ~14% “good” responses in one comparison), but may have fewer injection‑type side effects.[3] More research needed.
ILIT (intralymphatic)	Injections directly into a lymph node, usually monthly for a limited number of doses	Specialist/referral centers	In a small prospective study of 22 dogs, 89% had good and lasting responses, with rare minor side effects – better than SCIT (50%) or SLIT (14%) in that comparison.[3] Still experimental in many places.

Important nuance: Those ILIT numbers are very encouraging, but they come from a small study. We don’t yet know how they’ll hold up across larger, more diverse dog populations.

Safety: what’s known, what’s rare, and what to watch for

One of the quiet advantages of immunotherapy is its safety profile when used correctly.

What studies show

• ASIT is generally well tolerated.[2][3][5]

• Side effects can include:

  • Mild local reactions at injection sites (swelling, redness, tenderness).

  • Transient itch or discomfort after dosing.

• Systemic reactions (body‑wide effects like vomiting, facial swelling, hives, or breathing difficulty) are uncommon.

• Life‑threatening anaphylaxis is extremely rare. In one study of 185 dogs, there was one case of life‑threatening anaphylaxis.[2]

• Most systemic reactions, when they do occur, happen during the build‑up phase, when doses are being increased.[2]

ILIT and SLIT may have fewer or milder side effects than SCIT in some reports, but the data are still limited and protocols vary.[3]

From a caregiver’s perspective, the emotional weight of “this could go badly” is often heavier than the actual statistical risk. It’s reasonable to feel nervous about the first doses – especially injections – and that’s something you can and should talk through with your vet.

Timeframe: when (and how) results show up

Immunotherapy is a slow burn, not a quick fix.

Common timelines discussed in the literature and in practice:

• First hints of change:

  Some dogs show subtle improvement after 3–6 months.

  
  

• Fair trial period:

  Most dermatologists will say you need 9–12 months of consistent treatment before declaring ASIT a success or failure.

  
  

• Long‑term course:

  If ASIT is helping, treatment often continues for several years, sometimes longer. In some dogs, the dose or frequency can be reduced over time.

  
  

One large study found that regular veterinary follow‑ups in the first 9 months were associated with better outcomes.[1] That doesn’t mean more visits magically cure allergies – it likely reflects:

• Closer dose adjustments.

• Better management of flare‑ups.

• More realistic expectations and support for owners, which improves adherence.

In other words: staying in conversation with your vet improves your dog’s odds.

The quiet complication: steroids and other medications

Many allergic dogs are already on corticosteroids or other powerful anti‑itch drugs when ASIT is considered. These drugs are often necessary for comfort – but they can complicate immunotherapy.

The dilemma

• Systemic corticosteroids (oral or injectable) can interfere with the immune changes ASIT is trying to create, especially in the first months.

• However, some dogs are so miserable without them that stopping abruptly is not humane.

So vets walk a tightrope:

• Use enough symptom control to keep your dog comfortable.

• Use as little systemic steroid as possible, especially in the initial 9‑month window, to avoid blunting the effect of ASIT.[1]

This is rarely a clean, linear process. Expect adjustments, compromises, and the occasional flare. That doesn’t mean ASIT is failing – it means your vet is balancing biology with your dog’s real life.

Other supportive treatments – medicated shampoos, fatty acid supplements, topical therapies, newer targeted drugs – are often used alongside ASIT to smooth out the journey.

Why predicting response is so hard

You might reasonably ask: “Can we tell in advance if my dog will be in the 60% who improve?”

At the moment, not reliably.

What we do know:

Fairly solid:

• About 60–70% of dogs with atopic dermatitis improve meaningfully on ASIT.[1][2][5]

• Regular follow‑up and good adherence to protocols improve outcomes.[1]

• Serious side effects are rare.[2]

• ASIT can reduce the need for corticosteroids in responders.[2][5]

Still uncertain or emerging:

• Which biomarkers (blood tests, antibody levels, specific cell changes) predict who will respond well.

• The precise role of IgG4‑like antibodies and other immune shifts in dogs (we infer a lot from human data).[5][6]

• The best protocol for different dogs: SCIT vs SLIT vs ILIT, dose schedules, allergen mixes.

• Long‑term remission and relapse patterns: how many dogs can eventually stop ASIT and stay well?

• Whether certain breeds, ages, or allergy profiles respond better than others.

This uncertainty is frustrating, but it also explains why your vet might talk in probabilities and “let’s see how your dog does” rather than promises.

The emotional side: hope, fatigue, and the long middle

Living with a chronically itchy, uncomfortable dog is emotionally draining. Starting immunotherapy often brings a wave of hope – finally, something that treats the cause, not just the symptoms.

Then reality sets in:

• You’re giving injections or drops on a schedule.

• You’re watching closely for reactions.

• You’re going to the clinic for rechecks.

• Your dog still has bad days.

Many owners describe:

• Hope mixed with doubt – “Are we doing all this for nothing?”

• Guilt – “If I miss a dose, am I ruining the whole thing?” or “Should I have started this earlier?”

• Decision fatigue – weighing every flare: “Is this a setback or just normal variation?”

It may help to know:

• Even in strong responders, good days and bad days still happen. Allergies are influenced by seasons, infections, stress, and other triggers.

• Missing the occasional dose is usually not catastrophic; patterns over months matter more than one imperfect week.

• Feeling tired of the routine doesn’t mean you’re failing your dog; it means you’re human.

Veterinarians, for their part, carry their own emotional load: they know ASIT can help many dogs, but they also know they can’t guarantee it for yours. The best relationships are collaborative: shared decisions, shared uncertainty, shared victories.

Practical pros and cons: what you’re really choosing between

Here’s a more grounded look at the trade‑offs.

Potential benefits of desensitization and immunotherapy

• Treats the underlying allergic tendency ASIT is one of the few therapies that aims to modify the immune response, not just suppress symptoms.

• Meaningful symptom relief in many dogs Around 60% of dogs see at least a 50% improvement, with about 30% doing well enough that ASIT alone can control signs.[1][2][5]

• Reduced need for long‑term steroids In responders, this can lower the risk of steroid‑related side effects (weight gain, behavior changes, organ strain) over years.[2][5]

• Good safety profile Serious reactions are rare; most side effects are mild and manageable.[2][3][5]

• Quality‑of‑life gains Better sleep (for you and your dog), fewer infections, less constant licking and scratching – these are not small things.

• Potential long‑term stability Some dogs maintain improved control for years on ASIT; some may eventually reduce frequency or even discontinue, though we don’t have exact remission rates.

Limitations and downsides

• No guarantee of success About 40% of dogs have less than 50% improvement, even with good adherence.[1]

• Slow onset You may be months into treatment before you can say with confidence it’s helping.

• Cost and logistics  

  • Allergen testing and formulation of custom extracts.

  • Ongoing vials of allergen solution.

  • Recheck visits, especially in the first year.

  • Time and emotional energy to keep up with dosing.

• Technique and comfort  

  • If using SCIT, someone must be comfortable giving injections.

  • SLIT requires daily cooperation from the dog and consistency from the human.

  • ILIT requires specialist visits and sedation or careful handling for lymph node injections.

• Complex decision‑making with other medications Balancing steroids or other systemic drugs with ASIT goals is not always straightforward.

• Standardization issues Allergen extracts for dogs are not as standardized as in human medicine. Dogs also react to a wide range of environmental allergens, some of which are not fully defined.[7]

This is why the “Should we do this?” conversation is so individual. Two dogs with similar symptoms may have very different owners, budgets, schedules, and tolerances for uncertainty.

Questions to bring to your veterinarian

You don’t need to become an immunologist, but a few focused questions can make conversations more productive:

1. “Based on my dog’s history, what’s the realistic range of outcomes you’ve seen in similar cases?”Ask for stories or patterns, not just percentages.

2. “Which type of immunotherapy are you recommending (SCIT, SLIT, ILIT if available), and why?”Understanding the reasoning helps you commit to the plan.

3. “What will the first 12 months look like – in terms of visits, costs, and daily tasks?”Concrete expectations are easier to live with than vague “we’ll see.”

4. “How will we handle flares while we’re waiting for ASIT to work?”Discuss the role of steroids, newer medications, topical treatments, and how to avoid undermining ASIT while still protecting your dog’s comfort.

5. “What signs of side effects should I watch for, and what should I do if I see them?”Having a plan often reduces anxiety.

6. “How will we decide if ASIT is helping enough to continue?”You might agree on specific markers: fewer infections, reduced need for steroids, improvement on an itch scale, better sleep, etc.

These questions are not confrontational; they’re a framework for shared decision‑making.

When immunotherapy might be worth serious consideration

Immunotherapy is often particularly worth discussing when:

• Your dog has moderate to severe atopic dermatitis that recurs or persists despite basic management.

• You’re relying heavily on systemic corticosteroids or other strong medications and are worried about long‑term side effects.

• Allergy testing has identified clear environmental triggers (e.g., dust mites, grasses, trees) that can be used to formulate a targeted extract.

• You feel able – financially, emotionally, logistically – to commit to at least 9–12 months of treatment before judging success.

By contrast, if your dog has very mild, seasonal signs that respond well to occasional, low‑intensity treatment, the cost and effort of ASIT may not feel justified.

Neither choice is “more loving.” They’re simply different ways of caring within real‑world constraints.

The reality of “doing enough”

It’s easy, reading about a therapy that can modify the immune system, to feel that you’re failing your dog if you don’t pursue it.

The science doesn’t support that kind of moral pressure.

What it does support is this:

• Immunotherapy is a valuable tool for many allergic dogs, with a decent chance of meaningful improvement and a good safety profile.

• It is not a cure, not guaranteed, and not the only “right” choice.

• Your decision will sit at the intersection of:

  • Your dog’s severity and suffering.

  • Your financial and time resources.

  • Your comfort with injections, monitoring, and uncertainty.

  • Other available treatments and how your dog tolerates them.

A good veterinary team will help you weigh these factors without judgment.

If you do choose immunotherapy, you’re signing up for a long, somewhat unpredictable journey – but one that, for many dogs, leads to calmer skin, fewer drugs, and a quieter, more comfortable life.

If you don’t, you’re not giving up. You’re choosing a different path through the same landscape, doing the same fundamental thing: trying to keep your dog’s world as soft and bearable as you can.

Either way, understanding what desensitization and immunotherapy can and can’t do is not just academic. It’s a way of trading vague worry for grounded realism – and that, in itself, can make the road ahead feel a little more solid under your feet.

References

1. Bizikova P, Papich MG, Olivry T. Efficacy of subcutaneous allergen immunotherapy in atopic dogs: A retrospective study. Wiley Online Library. 2022.

2. DeBoer DJ. Allergen-specific immunotherapy for canine atopic dermatitis: Making it work. dvm360.

3. Marsella R. Allergen Immunotherapy for Canine Atopic Dermatitis: An Update. Today’s Veterinary Practice.

4. Pfaar O, et al. Effectiveness and safety of subcutaneous immunotherapy with Dpg-pol-cat in allergy patients. Frontiers in Allergy. 2025.

5. Canine ASIT: A Comprehensive Review of Efficacy and Future Directions. pro.dermavet.com.

6. Bousquet J, et al. Immunotherapy for pet allergies. Current Treatment Options in Allergy. PMC, NIH.

7. Durham SR, et al. Dog allergen immunotherapy: past, present, and future. PubMed.