Flea Saliva Allergy in Dogs 
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A flea saliva allergy usually manifests itself as severe itching.
Fleas are unwanted housemates for dogs, chiefly because they can transmit diseases with symptoms such as severe itching. Discover more about the development, treatment, and prevention of flea saliva allergy in your canine friend in this article.
Table of contents
- How Dangerous Is a Flea Saliva Allergy in Dogs?
- Symptoms: What Are the Signs of a Flea Saliva Allergy in Dogs?
- Diagnosis: How Is a Flea Saliva Allergy Diagnosed?
- Therapy: How Is a Flea Saliva Allergy in Dogs Treated?
- Causes: What Triggers a Flea Allergy?
- Prognosis: Is a Flea Saliva Allergy Curable?
- Prevention: Can a Flea Saliva Allergy in Dogs Be Avoided?
How Dangerous Is a Flea Saliva Allergy in Dogs?
A flea saliva allergy (informally known as flea bite allergy, flea dermatitis, or flea allergy) occurs when your dog’s immune system overreacts to flea bites (more precisely, flea saliva).
In many cases, this allergy is harmless, with strong itching being the most notable symptom. However, if your dog’s immune system overreacts too severely, it can lead to anaphylactic shock in the worst-case scenario – which can be life-threatening.
How Common Is a Flea Bite Allergy in Dogs?
Although antiparasitics for flea protection are common among dog owners, flea saliva allergy is considered the most common type of allergy in dogs.
Which Dogs Are Often Affected?
Since it takes some time for a flea saliva allergy to fully develop, dogs under six months old typically do not show this allergy. It is especially prevalent in dogs of middle to older age, and breed or gender plays no role.
Scientists believe, however, that the risk of developing this condition is greater the more often a dog is infested with fleas. A pre-existing condition of Atopic Dermatitis is also thought to increase the risk.
© Mi St / stock.adobe.com
Symptoms: What Are the Signs of a Flea Saliva Allergy in Dogs?
The severity of flea saliva allergy symptoms can vary from dog to dog. However, the most common signs of the disease include mild to severe itching, causing affected dogs to scratch or bite at their skin. This can lead to self-harm, visible as crusts on the skin.
Eventually, the skin may thicken, or nodules may develop, particularly in breeds like the German Shepherd.
Hair loss (Alopecia) and increased skin pigmentation are also common consequences of a flea allergy.
Inflammations Are Inevitable
Due to the constant nibbling and licking of the affected skin areas, it usually doesn’t take long for bacterial infections to occur.
Vets also frequently observe an accompanying infection with skin fungi (Malassezia pachydermatis) in dogs with a flea saliva allergy.
The resulting skin inflammation (Flea Salivary Dermatitis) can even manifest as Hot Spots.
Which Skin Regions Are Particularly Affected?
Skin changes due to flea saliva allergy typically occur at certain body sites including:
- Belly
- Legs (thighs)
- Flanks
- Hip
- Back (especially the rear area)
- Base of the tail and upper tail portion
When Do the First Symptoms Appear?
Dogs can display symptoms of flea saliva allergy in different ways. Depending on the type of allergy, the first signs of illness appear at different times.
With Type 1 (Immediate Type), symptoms are noticeable within 15 to 20 minutes. In the case of Type 4 (Delayed Allergy), your dog may not show discomfort until one to two days later. There is also an intermediate form, where symptoms occur approximately three to eight hours after contacting flea saliva.
When Should I Visit the Vet?
Sometimes you as a dog owner can spot fleas in your dog’s fur and take appropriate measures (flea treatment and hygiene).
If symptoms do not improve after this or if your dog shows signs of illness without clear evidence of flea infestation, it is best to consult your veterinarian.
Warning of Anaphylactic Shock
If your dog reacts with severe allergic reactions such as anaphylactic shock, it is an emergency. Signs include unconsciousness, difficulty breathing, and severe vomiting. In this case, seek veterinary help as quickly as possible.
For tips in serious cases, see our guide on First Aid for Dogs
Diagnosis: How Is a Flea Saliva Allergy Diagnosed?
The diagnosis of a flea saliva allergy typically follows a thorough owner interview (history) and clinical examination. For this, the vet needs information about parasite prevention as well as the timing of clinical signs.
In the meantime, he will usually perform a flea test by detecting fleas or flea faeces in your dog’s fur. If your dog responds to flea treatment, this is also an indicator of a flea saliva allergy.
The Allergy Test
To confirm suspicions, your veterinarian can carry out an allergy test. Blood may be drawn from your dog, or a skin test (intradermal test) may be conducted.
However, these tests are not completely reliable. As a result, a diagnosis of suspicion often occurs without an allergy test.
Therapy: How Is a Flea Saliva Allergy in Dogs Treated?
Since an allergy is incurable without desensitisation, the prevention of flea bites is central to allergy treatment. For this purpose, various antiparasitics for topical application are available.
For symptom relief, additional medications such as cortisone preparations may be used. Antibiotics for severe bacterial infections or antifungals for fungal infections may also be necessary.
Removing Fleas from the Environment
In addition to the medicinal treatment of a flea infestation in dogs, it’s important to take hygiene measures and remove all fleas from the environment.
Causes: What Triggers a Flea Allergy?
When a flea bites your dog, it secretes its saliva and sucks blood. This flea saliva contains certain proteins (allergens) that can trigger various allergy forms in your dog. The best-known of these allergens is called “Ctef-1”.
Do All Dogs with Flea Infestation Develop an Allergy?
The development of the disease probably involves an immunological process, which is why dogs respond individually to a flea bite.
Some develop an overreaction (Hypersensitivity), others develop immunological tolerance. Therefore, not all dogs with flea infestation automatically show a flea saliva allergy.
Which Fleas Can Cause a Flea Saliva Allergy in Dogs?
There are many different species of fleas worldwide. The cat flea (Ctenocephalides felis felis) is the most common one affecting dogs.
It is about two to four millimetres in size and can be recognised by its black-brown body. Typical of fleas: They jump like champions.
In Which Countries Are Fleas Present?
Fleas are present in almost all regions of the world, although the frequency of occurrence depends on the climate.
Fleas are especially common in mild to warmer regions, where they can live year-round. In colder regions like Scandinavia, fleas tend to have a seasonal life rhythm. For this reason, flea saliva allergy in dogs usually only occurs in the warmer months in cold regions.
Prognosis: Is a Flea Saliva Allergy Curable?
Allergies do not heal on their own, so without countermeasures, they can last a lifetime. However, if you are aware that your dog’s allergic reactions are due to flea bites, you can prevent the cause with appropriate flea treatments.
Prevention: Can a Flea Saliva Allergy in Dogs Be Avoided?
Dogs can develop allergies at any time, so you cannot prevent them entirely. For this reason, flea prophylaxis is essential if you want to avoid the occurrence of a flea saliva allergy in your dog.
Also, be mindful during walks that your dog doesn’t come into contact with flea carriers. Hedgehogs, for example, are typical wild animals that oftentimes teem with fleas.
This article from zooplus Magazine is purely informative. If your pet is experiencing discomfort, contact your veterinarian for diagnosis and treatment.
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At the Justus-Liebig-University of Giessen I was extensively trained as a veterinarian and was able to gain experience in various fields such as small animal, large animal and exotic animal medicine as well as pharmacology, pathology and food hygiene. Since then, I have been working not only as a veterinary author, but also on my scientifically driven dissertation. My goal is to better protect animals from pathogenic bacterial organisms in the future. Besides my veterinary knowledge, I also share my own experiences as a happy dog owner and can thus understand and enlighten fears and problems as well as other important questions about animal health.
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