Cytopoint for dogs: how the allergy injection works

Cytopoint is an injection that vets give to dogs to stop allergic itch. Its active ingredient, lokivetmab, is an antibody that blocks one of the main chemical signals telling a dog's brain to itch. It is not a steroid, it commonly starts working within a day, and one injection usually lasts four to eight weeks.

It is injected under the skin, normally by the vet or clinic staff. The amount is based on your dog's weight and is set by the vet, so this page gives no doses.

What is Cytopoint for dogs?

Lokivetmab is a monoclonal antibody: a laboratory-made copy of the kind of protein the immune system uses to lock onto one specific target. Its target is interleukin-31, a messenger released in allergic skin that switches on the nerves that carry itch. Cytopoint binds that messenger before it reaches the nerve.

With the signal blocked, the dog scratches, licks and chews less, and the skin gets a chance to heal. Vets use it for atopic dermatitis, which is allergy to things in the environment such as pollens and dust mites, and for other allergic skin disease.

It controls the itch. It does not remove the allergy, so the itch comes back as the injection wears off unless the trigger has gone.

Is Cytopoint a steroid?

No. Steroids damp down the whole immune response and act on many other body systems, which is why they can cause thirst, hunger, panting and longer-term problems. Cytopoint acts on a single itch signal. It is also not an antihistamine and not one of the daily anti-itch tablets.

Is it the same as an allergy shot for dogs?

People use "allergy shot" for two different things. One is Cytopoint. The other is allergen immunotherapy, a course of injections or drops made up for one dog after allergy testing, given over months or years to make the immune system less reactive. Immunotherapy is slow and aims at the allergy itself. Cytopoint is fast and aims at the itch. Some dogs have both.

How fast it works and how long a shot lasts

Many owners see less scratching within a day, sometimes sooner. One injection commonly lasts four to eight weeks, and the vet repeats it as needed. Some dogs only need it through their bad season. Others need it all year.

The response varies. Some dogs get the full eight weeks, some start itching again after three or four, and a minority do not improve much. If an injection did little, tell the vet. That can be a sign the itch has another cause, such as infection or parasites, that Cytopoint does not touch.

Cytopoint side effects

Side effects appear to be uncommon, and the product has been in wide use since the mid-2010s. Those that have been reported include:

• Tiredness for a day or two
• Vomiting or diarrhea
• Reduced appetite
• Soreness or a small swelling where the injection went in
• Rarely, an allergic reaction: a swollen face, hives, vomiting, weakness or collapse, usually soon after the injection

One practical point: an injection that lasts for weeks cannot be stopped the way a tablet can. If your dog has ever reacted to an injection or vaccine, say so before the first one, and report anything new you notice afterward, even if you are not sure it is connected.

Why vets often choose it for older dogs

Most medicines are processed by the liver or the kidneys. An antibody is not. The body breaks it down the way it breaks down its own proteins, and it has few known interactions with other drugs.

That makes it a common choice for an itchy senior who already has kidney disease, liver trouble, diabetes or heart disease, or who takes several medicines. Steroids can be a poor fit for many of those dogs. The vet still decides case by case.

There is one caution. Environmental allergies usually begin when a dog is young. When an older dog starts scratching for the first time, the vet will want to look for other causes before treating it as allergy:

• Fleas, mites and other parasites
• Bacterial or yeast infection of the skin or ears
• Hormone conditions such as hypothyroidism and Cushing's disease, which thin the coat and invite infections
• Less often, skin cancers that can look like a stubborn rash

Quieting the itch can hide these without treating them. Expect skin scrapes, tape samples and possibly blood tests first, especially if there is also hair loss.

Cytopoint injection cost

The price depends on your dog's size, the clinic and where you live. In the US, owners commonly report paying somewhere from several tens of dollars for a small dog to a couple of hundred dollars for a large one per injection, because the amount goes by weight. These are rough, variable figures, and only your clinic can give the real one. A first visit usually adds an exam fee and any skin tests.

Because it is repeated, at an interval the vet sets for your dog, ask the clinic for a quote for a full year, not one visit. Some pet insurance plans cover allergy treatment if the skin problem was not already present when the policy started. Check the wording on pre-existing conditions.

Cytopoint for cats

Cytopoint is not for cats. The antibody was built to match a dog's own antibodies so that a dog's immune system accepts it. A cat's immune system would treat it as foreign, so it is unlikely to work and could cause a reaction. It is not licensed for cats.

Itchy or over-grooming older cats need their own workup and their own medicines.

What Cytopoint does not do

• It does not kill fleas or mites.
• It does not treat skin or ear infections, which itch in their own right.
• It does not fix a food allergy. That takes a diet trial run by the vet.
• It does little for licking driven by pain, nausea or anxiety. See why old dogs lick everything.

Most allergic dogs need a combination: year-round flea control, treatment of any infection, medicated bathing and sometimes a diet change. Human antihistamines must only be given if your vet has confirmed the exact product and amount. Some versions contain decongestants or xylitol, which are dangerous to dogs.

Late or missed injections

Cytopoint is normally given at the clinic, so there is no dose to miss or double at home. If the itch returns before the next injection is due, call the clinic instead of adding leftover tablets or creams from a previous flare. If you miss a booked injection, rebook it. The main result of a late one is that the itch comes back.

If your dog sees another vet or an emergency clinic, tell them the date of the last injection.

Call the vet today if

• Your dog has a swollen face, hives, trouble breathing, repeated vomiting or collapse after an injection. This is an emergency.
• Tiredness, vomiting or diarrhea lasts more than a day.
• The itch has not eased within a few days, or returns within two or three weeks.
• The skin is red, wet, smelly, crusted or broken, or the ears are painful.
• Your dog is scratching until they bleed or cannot sleep.
• An older itchy dog also has new lumps, sores that do not heal, weight loss or increased thirst.

Questions to ask the vet

• What do you think is causing the itch, and what have we ruled out?
• Is there an infection to treat alongside it?
• How long should I expect this injection to last in my dog?
• What will a year of injections cost for a dog this size?
• Is it compatible with my dog's other conditions and medicines?
• What is the plan if it does not work or stops working?

This page is general educational information about Cytopoint (lokivetmab), not veterinary advice, and it does not endorse any product. Whether the injection suits your dog, how much is given and how often it is repeated are decisions for your own veterinarian after examining your dog's skin. Prices are commonly reported ranges and vary widely, so ask your clinic for a quote.