Dogs can become itchy and begin to scratch for many different reasons. However, allergies of various types are among the most common causes.
Canine Flea Allergy Dermatitis
A flea allergy is one of the most common reasons dogs become itchy. When a flea bites a dog, it injects a substance into the dog’s skin which causes an allergic response.
For a sensitive dog, one flea bite can make the dog incredibly itchy.
The problematic thing about flea allergy is accepting they might be a problem. Just because you don’t find evidence of fleas doesn’t mean that is not what your dog is reacting to. Fleas might not infest your dog. Remember that all it takes is a bite from a single flea to trigger the allergic reaction. You’ll never find evidence of one flea.
In addition, dogs frequently groom themselves and remove the evidence of fleas through their grooming behavior. The absence of detectable fleas does not rule out a flea allergy as a cause of itching in a dog.
Canine atopy is an allergy that causes a hypersensitivity reaction to environmental stimuli, such as dust mites or pollens. It is a common disorder in dogs and typically causes scratching and itching. Finding the source of the allergy in these cases can be challenging.
Food allergies are another common cause of itching in the dog. Itchiness can result from reactions to any ingredient in the food but beef, chicken, and what are some of the most common culprits.
Bacterial infections in the skin, commonly called bacterial dermatitis, are another common cause of itchiness in dogs. They frequently occur as complications of canine allergic skin disease and are usually secondary disease.
The infection must be successfully treated with antibiotics to evaluate and control the underlying allergic skin condition.
Canine Yeast (Malassezia) Skin Infections
Yeast skin infections most commonly involve a specific type of yeast known as Malassezia. Like bacterial skin infections, yeast infections are generally secondary to another underlying disease, often allergic in origin. Therefore, antifungal medications, such as ketoconazole, are needed to treat canine yeast infections.
Most Common Causes of Itching in Dogs
The three most common causes of itching in dogs are flea dermatitis, atopy, and food allergies.
These three types of allergies can be complicated, with secondary bacterial or yeast invaders resulting in bacterial and/or yeast skin infections in affected dogs. These skin infections can become quite itchy in their own right and cause extreme discomfort and distress for the infected dog.
Less commonly, other causes, such as canine ringworm (dermatophytosis) or sarcoptic mange, may also cause itchiness and discomfort.
Editor’s update on atopic dermatitis – the genetic link
A 2022 study at Uppsala University and the Swedish University of Agricultural Sciences discovered a genetic link to canine atopic dermatitis.
New gene mapping science allowed the identification of a region that represents a significant risk factor–filaggrin gene region. Filaggrin is a protein involved in the function of the epidermal barrier. This protective barrier prevents dehydration, absorption of toxic substances, and infections. When this barrier fails to function, it leads to atopic eczema in people and atopic dermatitis in dogs.
While environmental factors play their role in the development of atopy in dogs, as it turns out, the problem has complex genetic roots.
“The new methods make it possible to find new risk factors that have become common in the specific breed, perhaps because of the selection for other characteristics,”Katarina Tengvall, researcher at Uppsala University and first author of the study.
Understanding the genetic component and the disease mechanism can lead to better therapies.
Further reading: Atopic dermatitis in dogs linked to certain parts of the genome
Intense Scratching in Dogs