Symptoms of Flea Collar Poisoning + Side Effects of Seresto, Hartz, Salvo, etc

Flea collars have been used to kill and repel fleas for a long time. They have remained popular because of their simplicity and effectiveness, although other flea prevention products have emerged like oral tablets, dips, shampoos, etc. 

Basically, their mode of action is to release pesticides into your pet’s sebaceous glands and hair follicles, and upper back. This causes the pests to move from the head and neck area to the base of the tail, where they eventually die and fall off. Keep in mind that there are different types of flea collars, such as ultrasonic, herbal, gas-emitting, and more. 

In most cases, flea collar effectiveness lasts for 90 days, after which you should replace them. However, some modern designs like Seresto can last up to 8 months. Unfortunately, these collars have side effects such as redness, scratching, hair loss, and more. 

Do you have a specific question about the symptoms of flea collar poisoning? Then use the table of contents below to jump to the most relevant section. And you can always go back by clicking on the black arrow in the right bottom corner of the page. Also, please note that some of the links in this article may be affiliate links. For more details, check the Disclosure section at the bottom of the page. 

Allergic reactions to the flea collar 

Most people prefer flea collars on their dogs because of the convenience. It remains in one place while the active ingredient spreads throughout the dog’s fur gradually. However, this can cause your dog to develop multiple types of allergies.

The most common ones are respiratory and contact allergies, but sometimes they can even lead to death. Remember that the severity of the allergies may vary from mild to severe. Symptoms include watery eyes, runny nose, coughing, sneezing, wheezing, skin inflammation, itchy skin, lethargy, and death. 

Take your dog to the veterinarian immediately if you see any of these symptoms after putting on the flea collar. The sooner the dog gets treatment, the higher the chances of full recovery. 

Dog flea collar Seresto side effects

The Seresto flea collar is regularly featured on most online reviews of flea collars for dogs. However, it has recently been associated with thousands of pet injuries and even death.

According to documents obtained from the US Environmental Protection Agency (EPA), the Seresto collar causes lethargy, scabs on the skin, motor function loss, and seizures. In fact, there have been more than 75,000 incident reports since the collar was introduced in the market in 2012. 

Making matters worse, the Seresto flea collar affects even human beings. Common side effects include numbness, skin rashes or lesions, throat irritation, tingling, etc. These signs manifest after placing the collar on the pet. 

Hartz flea collar side effects

Hartz is also a popular flea collar for dogs. However, the collar has been receiving many complaints that it negatively affects pets instead of killing and repelling fleas. Its side effects include fur loss around the neck, lethargy, and rashes after tying the collar on the dog.

Besides the flea collar, other pet products under the Hartz brand have also received a lot of criticism. So, if you are using any of these products and start noticing any abnormal behaviors with your pet, consult the veterinarian immediately.

Adams Flea and tick collar 

Adams Flea and tick collar is marketed as a highly effective remedy for fleas and ticks on canines. It works similarly to other products in the category where it gradually releases a pesticide formula to kill and repel parasites. But, according to the manufacturer, the collar will start to act immediately when you place it around your pet’s neck. 

However, it causes allergic reactions and irritations, which can be severe sometimes. Also, the label indicates that you shouldn’t use the collar on puppies under 12 weeks. 

Moreover, Adams flea and tick collar is also harmful to human beings. Therefore, you should avoid contact with your skin, eyes, or even clothes. 

Sentry Flea and tick collar side effects

Sentry Flea and tick collar will provide your dog with a long-lasting relief against parasites. It comes as a pair and offers protection for up to 12 months from pests that cause Rocky Mountain spotted fever and Lyme disease. 

However, the collar causes side effects like anxiety, itching, swollen eyes, restlessness, whining, and severe rash. It also affects human beings, so you should avoid contact with eyes, skin, and clothing. 

Salvo flea collar side effects 

The Salvo Flea and tick collar come as a pair, and each will provide your dog with 6 months of protection against parasites. It has a double-layer release system containing deltamethrin.

It works by combining the insecticidal actions of powder and vapor, safeguarding your pet from head to tail. The manufacturer indicates that you should expect maximum effectiveness 2-3 weeks after placing the collar. 

Unfortunately, the collar may have some side effects on your dog, such as lethargy, rashes, itching, twitching, dry skin, chemical burn, and twitching. Also, it is advisable to wash thoroughly with soap after handling it as it irritates your skin or eyes.  

Symptoms of flea collar poisoning in a dog

The chemicals found in most flea and tick collars that help eliminate parasites can be harmful if ingested. For example, they can cause severe effects on the nervous system resulting in neurological deficits. 

Moreover, these collars can leave residue on the dog’s hair that can last for weeks. Besides ingestion, poisoning can also occur by licking the residue on the hair. Therefore, you should be aware of the potential risks to children and other household pets. 

Amitraz and propoxur are two common chemicals found on most flea and ticks collars. They can cause severe toxicity if your dog ingests the collar accidentally.

Below are some of the general symptoms of flea collar poisoning in dogs: 

● Loss of bodily movement control 

● Weakness 

● Depression 

● Diarrhea 

● High or low body temperatures 

● Urinary incontinence 

● Muscle twitching 

● Vomiting 

● Seizures 

● Excess salivation 

● Difficulty breathing 

● Dilation of pupils 

● Abnormal heart rhythm 

Furthermore, other dangers of flea collars can be loss of hair, redness of the skin, and constriction of the eye’s iris. Apart from amitraz and propoxur, tetrachlorvinphos is another chemical used in flea and tick collars. This is an organophosphate that affects a dog’s nervous system. 

The best flea collar poisoning treatment is medication and support therapy. Also, the veterinary can induce vomiting depending on the chemical in the collar, timing, and state of the pet. In addition, activated can be effective in bidding the poison.

Are flea collars safe for dogs?


Flea and tick collars are the most popular method of preventing and killing and preventing pests on dogs and other pets. Essentially, these collars work by distributing pesticides to the pet’s skin or emitting harmful gas to the parasites.

Sadly, these features that make the collars effective at keeping the pests at bay can be hazardous to pets and humans. For example, exposure to the chemicals found in the collars can cause severe and life-threatening side effects. 

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