While it may be remarkably cute for a dog to be scratching his floppy ear with a look of relief-induced bliss on its face, the fact of the matter is that something is causing that dog to itch. The scratching, rolling and rubbing is a reaction mechanism in which the dog is trying to separate the irritant from itself. Have you been thinking, “why is my dog itching?” Let's go to science.
Just like in humans, there are various causes and irritants that may make a dog itch, everything from bugs to the environment to its food and even culprits that can only be identified under a microscope. As a dog owner, it is important to recognize the symptoms, seek a proper diagnosis and implement the correct treatment plan.
It's important that you consult your veterinarian when you notice your dog itching more than normal. While it's probably a quick fix, it could also be a symptom of a more serious illness.
Why Is My Dog Itching?
here's what science says and what you should do
Of course, the first and most common, obvious cause of itching in dogs.
These small insects have become synonymous with the bites, rashes and frustrating itch on dogs that comes along with such an encounter. Dogs are especially susceptible as they are lower to the ground and closer to vegetation which is where fleas tend to wait in ambush.
The itching is known as flea allergy dermatitis and is usually caused by the fleas' saliva (Baker et al. 1975). The saliva gets on and inside the skin of the dog after being bit by the flea resulting in a hypersensitive reaction. Extreme (and sometimes painful) itching will usually occur, along with a bite “bump” and some signs of dermal irritation around the wound.
The inflamed response so characteristic with flea bites can form in as little as 15 minutes from being bit to as delayed as 48 hours from being bit. Since every dog is different in both anatomy (size, height and weight) and physiology (how each individual responds to a stress) the reaction time will vary. But, make no mistake it will appear sooner or later.
Surprisingly, one of the more common species of fleas that can be found on dogs, comes from cats (Durden et al. 2005).
The cat flea has been shown to bite more dogs than the more logical dog flea or the more typical generalist/carnivore flea. It is theorized that since more cats (both feral and domestic) are allowed to wander outside the home, then they have a higher potential of spreading cat fleas onto dogs who hang out in areas where they once prowled.
Today’s veterinarians have at their disposal a veritable arsenal of tools to fight and protect against fleas. These flea control and treatment practices range from flea drops, flea shampoos, flea powders, flea pills, flea collars and even flea carpet sprays for your home.
The problem with fleas is that they have the ability to reproduce at such a fast rate that it’s not just a matter of dealing with a single flea but you must also deal with its buddies and all their eggs. The first step would be to give the dog a quick bath to remove detritus and debris from its coat and skin. This will make it tougher for fleas to hide.
Are there any scientifically proven solutions to fleas?
Yes. There are topical creams such as selamectin. Studies have shown that it's one of the most effective killers of fleas (McTier et al. 2000). It is an adulticidal (will kill mature fleas), ovicidal (kills flea eggs) and larvicidal (kills flea larvae). This step must be repeated for a couple of days until comb counts reveal a very low to completely nil flea count.
You'll need a long-term flea preventative. Slow-release matrix collars allow substance and compounds to be stored within them and will slowly release these over a period of time.
Take imidacloprid/flumethrin for example, a solution that's also been proven effective against fleas and ticks on dogs (Stanneck et al. 2012). These can be stored in dog flea collar treatments and have been shown to keep 95% of adult fleas and 99% of flea larvae off the dog for up to 8 months.
Finally, clean your home after flea encounter.
Do some research on how to get rid of fleas on the dog and around your house. The process may be time-consuming, but it's absolutely necessary once you encounter fleas on your dog (they are sure to be in your home or backyard as well). Here's a video guide on getting rid of fleas around the house and on your dog quickly and effectively.
The more dangerous parasite that's on every pet owner's mind.
Unlike fleas, ticks have become synonymous with disease and death in both dogs and humans. While some may claim that it is merely Lyme-hysteria, the fact remains that lyme disease is very real and is transmitted by ticks. If the answer to your question, “why is my dog itching” happens to be ticks, it's likely going to cause a bit of panic.
Besides Lyme disease, ticks are also a vector of host of other diseases. Southern tick-associated rash illness (STARI), Rocky mountain spotted fever (RMSF), ehrlichiosis and tularemia can also be carried by ticks. Besides the rashes and itching that are indicative of their presence, they can also bring with them fever, chills, aches and pain.
The uninformed may say that deer ticks (known to usually carry Lyme disease) are only found in the cold deep woods or some remote back-country; however, there is scientific evidence to suggest that disease carrying ticks can now be found in temperate zones and urban centers, and much more commonly in the US (Shaw et al. 2001).
This is a cause of considerable concern, as the range of ticks is effectively widening to include areas where they were not normally found.
Much like fleas, ticks easily find their ways onto dogs due to canine's proximity to the ground and brush, as well as dog hair providing an easy point of attachment. While it may be logical to think that the majority of ticks would be concentrated on the legs, shoulders and muzzle of the dog, it has been observed that ticks are pretty much evenly distributed over the entire body. However, studies have shown that flea larvae are usually found in the dog's ears, where it is moist and sheltered (Kosch 1982).
Ticks are parasites. They feed off the host, the dog in this case, and infection management and treatment would greatly benefit from understanding not only the life cycle of the flea, but also the ecological condition in which they thrive in (Dryden et al. 2004).
Treatment for ticks is a bit trickier than you would think. There are several species of ticks and each can carry a different disease than the other. There is no blanket treatment when it comes to ticks on your dog, and each case must be dealt with on an individual basis.
The main step to take would be to prevent getting your dog bit by ticks in the first place. But if your dog has already been bit by a tick, are there any scientifically proven solutions to deal with a tick bite? Fortunately, yes – there are.
In the event of a tick bite, studies have shown that a combination of imidacloprid and permethrin has a far greater effect in treating tick bites than the combination of fipronil and methoprene (Otranto et al. 2005).
While this form of treatment may exist, the best way to reduce the chances of your dog acquiring a tickborne disease is to regularly check your dog, especially after spending time in the outdoors. Use a tick removing tool to carefully remove ticks from your dog as soon as you find them on him.
Speak with your veterinarian to see if there are any tick-borne diseases in your area and any areas where you may be visiting and exploring with your dog. And while you’re at it, talk to your vet about tick preventatives. There are several products in the market that were designed to ward away ticks.
FULL GUIDE: How To Remove A Tick From A Dog
3 Allergic Environmental Dermatitis
There are more sources of it than you may think.
Dogs exposed to mites in the environment often bring about an allergic reaction that causes them to itch uncontrollably. This condition has been dubbed canine atopic dermatitis, or cAD, has been studied extensively over the last decade (Hill et al. 2001). However, during the exploration of this condition, researchers have noticed that it is not only mites that triggers cAD, but also other allergens such as house dust, pollen, mould spores and different antigens.
If you suffer from allergies, you know how frustrating it can be to deal with. Now imagine that same feeling only you are not able to convey it to anyone besides scratching. This is how dogs with canine atopic dermatitis feel.
Are there any science-based treatments for this?
Yes. Dextromethorphan, an oral medication, has been shown in studies with dogs to have significant effects on decreasing licking, chewing and biting of themselves (Dodman et al. 2004).
Used in conjunction with some slight canine behavior modification, the use of Dextromethorphan has been observed to be an effective means of managing the effects of cAD.
Furthermore, an AVMA study have observed that Triamcinolone acetonide topical solution (TTS), a topical spray, can be used to decrease the inflammation that often comes with this form of canine dermatitis (DeBoer et al. 2002). With few and no more than mild side effects, TTS is an effective short term way to decrease inflammation, itching and scratching that allergen-based dermatitis brings to the life of your pet.
4Canine Nutritional Dermatitis
What many pet owners still do not suspect.
Where allergen based dermatitis in dogs is inflicted by the external world, nutritional dermatitis occurs when a dog's system is afflicted by something he has ingested. Food allergies are not unique to humans. Dogs can also display sensitivity to different types of foods and in turn, this causes what is known as nutritional dermatitis.
There is no broad stroke definition or list of foods to avoid, as nutritional dermatitis can be triggered by different foods, depending on the dog. While there are labeled hypoallergenic dog food brands, none of them are actually 100% hypoallergenic for dogs. I recommend you read this article from our DVM to understand why they aren't.
Instead, because we can't avoid feeding dogs food altogether, we need to understand what causes the allergic reaction in dogs and then block it. We know that allergic reactions usually trigger a histamine release in dogs which causes inflammation, redness, swelling and itching. So, to battle nutritional dermatitis in dogs is a matter of managing or preventing histamine release.
How do you manage or prevent histamine release in dogs?
One of the best ways to do this is by using conjugated linoleic acid (CLA), which has been observed in studies to significantly inhibit the effects brought upon by the release of histamine (Bloom 2008). This is one of the most effective ways to deal with nutritional allergies and topic dermatitis in dogs.
Alternatively, the oral intake of probiotic Lactobacillus rhamnosus strain GG reduces the allergic reactions brought upon by this form of dermatitis (Marsella 2009). This has been observed in many human trials as well. Moreover, there are other benefits of giving probiotics to dogs, all of which are related to significant health improvements through canine's gut flora and microbiota.