The most common shot vets give dogs for itching is Cytopoint, a targeted injection that reduces itch within 24 hours and lasts four to eight weeks. Steroid injections are also used for acute flare-ups, and allergy desensitization shots offer a longer-term approach. Here’s how each one works, what they cost, and what to expect.
Cytopoint: The Go-To Itch Injection
Cytopoint is a lab-made antibody designed specifically for dogs. It works by neutralizing a protein called interleukin-31 (IL-31), one of the main chemical signals that triggers itching in dogs with allergic or atopic dermatitis. Normally, IL-31 binds to receptors on nerve cells in the skin, firing off itch signals to the brain. Cytopoint intercepts that protein before it reaches the nerves, so the itch signal never gets sent.
Because the injection targets one specific itch pathway rather than suppressing the whole immune system, it carries a lighter side-effect profile than older options like steroids. The antibody is “caninized,” meaning it’s engineered to look like a natural dog antibody, which reduces the chance of the body reacting against it.
How Fast It Works and How Long It Lasts
Most dogs get noticeable relief within 24 hours of the injection. The effects typically hold for four to eight weeks, at which point your vet can give another shot if symptoms return. Some dogs consistently need it every four weeks during allergy season, while others go the full eight weeks between visits. Your vet will adjust the schedule based on how your dog responds.
If itching hasn’t improved within a day or two, continued Cytopoint injections are unlikely to help that particular dog. Neither Cytopoint nor its oral counterpart works for every case, and some dogs that respond well initially stop responding over time.
Side Effects of Cytopoint
Serious reactions are rare. The European product summary classifies the following as rare (affecting fewer than 1 in 1,000 dogs treated): vomiting, diarrhea, and hypersensitivity reactions like facial swelling or hives. Neurological signs such as seizures or loss of coordination have also been reported rarely in post-market monitoring. Most dogs tolerate the injection with no noticeable side effects at all.
What Cytopoint Costs
The price depends on your dog’s weight, since the dose scales with size. Expect to pay roughly $50 per injection for a small dog, $100 for a medium dog, $150 for a large dog, and $200 or more for giant breeds. If your dog needs shots year-round (up to 12 per year), annual costs can range from $600 for a small dog to $2,400 for a giant breed. Dogs with seasonal allergies who only need three or four shots a year will pay considerably less.
Steroid Injections: Fast but Not Ideal Long-Term
Before Cytopoint became widely available, steroid injections were the standard quick fix for severe itching. Vets still use them, particularly for acute allergy flare-ups that need immediate relief. A single intramuscular injection of dexamethasone, one of the most common options, can reduce itching within an hour.
The tradeoff is that steroids suppress the immune system broadly. Short courses of a few days are generally well tolerated, but repeated or prolonged steroid use carries real risks: increased thirst and urination, weight gain, elevated blood pressure, and salt and water retention. Over the long term, steroids can suppress the adrenal glands (leading to a condition resembling Cushing’s syndrome), unmask hidden diabetes, weaken bones, and increase susceptibility to infections. That adrenal suppression can persist for months after the steroid is stopped.
For these reasons, most veterinary dermatologists now reserve steroid injections for short-term crisis management rather than ongoing itch control. If your dog needs relief beyond a single flare-up, your vet will likely steer toward Cytopoint or an oral medication instead.
Cytopoint vs. Apoquel
Apoquel is the main oral alternative to Cytopoint. Both begin working within 24 hours, but they differ in how they’re given and what they target. Cytopoint is an injection administered at the vet clinic every four to eight weeks. Apoquel is a daily tablet you give at home.
Apoquel blocks a broader range of inflammatory signals beyond just IL-31, which can make it more effective for dogs dealing with skin and ear infections alongside their itching. On the flip side, Cytopoint’s narrower target means fewer potential drug interactions and side effects. Some dogs respond to one but not the other, and your vet may try both before settling on the better fit. In some cases, neither works, and a different strategy is needed.
Allergy Desensitization Shots
If your dog’s itching stems from environmental allergens like dust mites, pollen, or mold, your vet may recommend allergen-specific immunotherapy. This is a different kind of injection entirely: rather than blocking itch signals, it gradually trains the immune system to stop overreacting to specific allergens. Your dog receives small, increasing doses of the substances they’re allergic to, typically identified through skin or blood testing.
This approach has a success rate of 50 to 70% in dogs with atopic dermatitis when given for up to 12 months. “Success” in clinical studies means at least a 50% reduction in itching and skin lesions. Some newer formulations show improvement within three months, while traditional versions may take nine months or longer to reach full effect. Immunotherapy won’t provide the instant relief of Cytopoint or steroids, but for dogs that respond, it addresses the root cause of allergies rather than just masking symptoms. Many dogs still need Cytopoint or another treatment to manage itching during the months it takes for immunotherapy to kick in.