With so many over-the-counter medications readily available to humans, it can be tempting to reach for our own medicine cabinet when our pet needs help. However, not only is this illegal, it can also be dangerous for your pet. With summer being the peak season for insect stings and bites, let’s take a look at why reaching for the antihistamines isn’t a good idea. 

What is an antihistamine?  

Histamine is a chemical released in the body during an allergic response. It causes the symptoms we see, such as hives and itching. Antihistamines such as diphenhydramine work by blocking histamine receptors. So, while they don’t stop histamine being released, they do stop the body from responding to the histamine. 

Which insects could bite or sting my pet? 

The most commonly seen insect bites or stings (in the United Kingdom) include: 

  • Wasps: As you may know yourself, wasp stings can be very painful! Wasps also have a tendency to sting multiple times, especially if they feel threatened. Wasps don’t leave their stinger behind. 
  • Bees: Bee stings are also painful, and they leave their stinger behind, meaning they only sting once. 
  • Hornets: Hornet stings are perhaps considered the most painful by humans. Like wasps, they don’t leave their stinger behind, so can sting multiple times. Luckily, they tend to be more docile than wasps, and only tend to sting if their nest is disturbed.  
  • Mosquitos: Mosquito bites don’t usually cause much of a problem in pets. Usually, you won’t even notice they have been bitten! You may notice your pet scratching, or a bite reaction much like in people. 
  • Ants: Ant bites also rarely cause an issue. You may notice small, red spots if you look very carefully.  
  • Fleas: We all know pets can be bitten by fleas! It’s also fairly common for pets to be allergic to flea saliva, meaning they itch intensely when bitten. This can cause a nasty rash and secondary infections if left untreated. 

Now let’s take a look at how to tell if your pet has been bitten or stung by an insect. 

Symptoms of insect bites or stings in pets 

Insect bites or stings are common in pets. They are especially common in dogs, since they tend to be less discerning than cats when exploring! For this reason, dogs are most often bitten or stung around their face, in their mouth, or around their paws; while they rummage through the grass or try to catch the insect in their mouths. You may hear your pet cry out if they are stung. 

Signs of minor insect bites or stings in pets include: 

  • Mild swelling 
  • Red, raised bumps 
  • Licking or biting a specific area 
  • Pawing at a localised area 
  • Vocalising (when the sting happens) 
  • Limping (on the leg that has been bitten or stung) 

Many insect bites or stings only cause mild signs, and can be managed at home. However, some are more serious, especially if your pet has an allergic reaction. 

Red flags: when to see a vet 

Allergic reactions to insect bites or stings are also pretty common. More serious symptoms of insect bites or stings in pets include: 

  • Hives 
  • A nasty rash 
  • Intense pain and / or itching 
  • Rapid, localised swelling (around the affected area) 
  • Drowsiness or lethargy 
  • Vomiting 
  • Trouble breathing 
  • Fast breathing and / or heart rate 
  • Drooling 
  • Collapse or fainting  

These indicate that your pet is having an allergic reaction, and you need to seek veterinary attention immediately. Allergic reactions are particularly serious if the bite or sting is around the face, neck, or in the mouth. Rapid swelling in these areas can interfere with your pet’s ability to breathe.  

Flea bite allergies are not an emergency, but they do need veterinary treatment. Flea bite hypersensitivity causes a rash with small scabby red spots. It is very itchy, so your pet would lick, scratch or rub themselves more. If left untreated, this can lead to fur loss, a more serious rash, or a secondary skin infection.  

Check your pets symptoms
Symptom Checker

What to do if your pet has been bitten or stung 

If your pet is only showing mild signs, you can try to treat the bite or sting at home. The first thing to do is check for a stinger. If you can see a stinger sticking out, try to gently scrape it off with something firm, like a bank card. It’s best to avoid using tweezers or your fingers, since squeezing the stinger can release more venom from the stinger into your pet.  

If your pet allows, you can place an ice pack wrapped in a thin layer of material (like a tea towel) over the affected area. This reduces swelling and soothes the area. Keep an eye on your pet, and watch out for signs of an allergic reaction. If you aren’t sure, call your vet practice for advice. 

If your pet is showing any more serious symptoms, or signs of an allergic reaction (or you aren’t sure) you should seek veterinary help immediately. 

Can I give antihistamine to my pet? 

There are no antihistamines licensed for use in pets. So, the short answer is no, you cannot give antihistamine to your pet! It’s actually illegal in the U.K. to give a human medication to your pet without a veterinary prescription. In an emergency, your vet may advise you to give a medication that you already have at home, in which case you must follow their instructions carefully.  

In some situations, your vet may prescribe an antihistamine (human medication) to your pet. This would be ‘off license’, under the veterinary prescribing cascade. Under the cascade, vets can prescribe human medications if there is no licensed veterinary alternative.  

Antihistamines are actually less effective in pets than in humans. This is because dogs’ and cats’ immune systems are different from ours: their immune systems rely less on histamine during allergic reactions. Instead, dogs’ and cats’ immune systems rely more on other inflammatory mediators during allergic responses. Since the use of antihistamines is both off license and less effective than available veterinary medications, it is uncommon for vets in the UK to prescribe antihistamines.  

There are special circumstances where your vet may consider antihistamines the best choice and prescribe them for your pet. If your vet does prescribe an antihistamine, it’s important that you ONLY use the specific antihistamine that your vet has prescribed, and only in the pet that it has been prescribed for. Some antihistamines are not safe for pets. Human antihistamines can also contain other ingredients, such as decongestants or xylitol, which are toxic to pets. 

How to prevent insect bites or stings 

It is hard to avoid insect bites and stings in pets (much like it is for us)!  

Teaching your dog not to chase wasps or bees (by distracting them with something more interesting like a yummy treat) will reduce the chance of a nasty sting to the mouth or face.  

Naturally, avoid going near any known wasp or bee nests with your pet!  

You can get insect repellants for pets if you are having ongoing issues, but they aren’t always effective. Be sure to only use ones designed for your type of pet (dog products are often toxic to cats, for example).  

If your pet has an allergy to flea bites, ask your vet about ongoing flea prevention. 

Key Points 

Insect bites and stings are more common in spring and summer. They are typically seen in dogs more than cats. Common sites for insect bites or stings in pets include around the face, mouth or paws. 

Most insect bites or stings in pets are mild and can be treated at home. However, if you aren’t sure, you should always phone your vet practice for advice. 

If your pet is showing more severe signs, signs of an allergic reaction, or they have been stung multiple times, you should seek veterinary attention straight away.