This article outlines the primary causes of itching in dogs, including ectoparasites like fleas and mites, allergic reactions, infections, and hormonal issues. Symptoms such as scratching and licking are key indicators for pet owners. A veterinary examination is essential for accurate diagnosis, which may involve various tests. Treatment options include proper diagnosis, dietary changes, medications, and preventive care to ensure your dog’s skin health and alleviate itching.
Have you ever been kept up all night by the sound of your dog constantly licking and chewing on themselves? If so, you can relate to the frustration this causes for many pet owners, in addition to the significant discomfort that excessive itching can cause for your dog.
In this article, we will discuss what itching can look like, common and uncommon causes of itching, and how to provide much-needed itch relief for your dog.
What Itching Looks Like in Dogs
To know when to seek veterinary treatment for your itchy dog, you first need to be able to recognize the various manifestations of pruritus (itching). You may notice the following signs:
Dogs can have generalized itching all over the body, or more specific areas that are itchy.
Itching can manifest as scratching (side of body, head, neck), chewing (limbs and paws), and licking (limbs and paws).
Itchy ears will often cause dogs to shake their heads frequently, or they may whine in pain when they scratch their ears.
Excessive scratching may be more evident at night, and your dog may be disrupting your sleep.
Depending on the cause of the itching, hair loss may be present.
If your dog has a skin infection, their skin may be red and swollen, have bumps such as pustules (pimples), scabs, or other lesions, exude a colored discharge, feel either greasy or very dry, or have a bad odor.
Common Causes of Itching in Dogs
Itching is a symptom, not a specific disease. There are numerous possible underlying causes of itching in dogs, which can make diagnosis and treatment equally frustrating for the dog, the dog owner, and the veterinarian. The following are some of the most common causes of itching in dogs:
Ectoparasites
Several types of skin parasites, or ectoparasites, can cause your dog to itch. Fleas, mites, and lice are three common ectoparasites that can invade the skin and hair of dogs and cause moderate to severe itching. While fleas and lice are visible to the naked eye, mites (including Demodex and Sarcoptes) can only be identified under a microscope.
Fleas and flea bite allergy: These small parasites feed on a dog’s blood and may cause itching, hair loss, and secondary skin infections. Some dogs can also develop an allergy or “hypersensitivity” to flea bites (specifically, flea saliva), known as flea allergy dermatitis. While most dogs will exhibit some degree of scratching as a result of fleas, these dogs have a more significant reaction leading to intense itching.
Mange mites: The two most common types of skin mites in dogs are Demodex and Sarcoptes, which are sometimes referred to as Demodectic Mange (“red mange”) or Sarcoptic Mange (“scabies”). Demodex are mites that live inside or near the hair follicle, while Sarcoptes are a burrowing mite that go deeper into the skin. Both can cause itching; however, intense itching is more commonly seen with Sarcoptic Mange. Dogs naturally have small numbers of Demodex on the skin, but infection and clinical signs arise when the infestation becomes too great, usually in animals that are young or immunocompromised.
Lice: The final type of ectoparasite that can cause itching in dogs is lice. Luckily, lice are host-specific, meaning lice on your dog cannot be passed to other species or people living in the home. Unlike fleas, lice do not survive off of their host for more than a few days, making treatment of the dog and environment relatively straightforward. Lice are visible to the naked eye, can often be seen moving, and are pale in color. While lice can lead to itching and scratching in your dog, they do not tend to cause significant damage to the skin or other issues.
Allergies
Allergies are a common cause of dog itching when no fleas or other ectoparasites have been identified. Allergies in dogs are often divided into two categories – food allergies and environmental allergies (also known as atopy or atopic dermatitis).
Food allergies can lead to itching when a dog is allergic to something in their diet, usually a protein source. Environmental allergies are caused by something in the environment, such as pollen. It is not uncommon for dogs to be allergic to more than one thing.
They can lead to scratching, redness, and recurrent skin and ear infections as a result of an immune-mediated and inflammatory response to an allergen. Food allergies may also cause gastrointestinal issues in some cases, while environmental allergies may have a seasonal component. For more information on dog allergies and treatment options, visit our page “Dog Allergies: All You Need to Know From Symptoms to Treatment.”
Infections: Bacteria vs. Yeast
Infections caused by bacteria or yeast are another common cause of scratching. While small amounts of bacteria and yeast are naturally present on the skin of dogs, an overproduction of either can lead to infection. Skin infections can cause pain, discomfort, and itching in dogs. Malassezia, a type of “budding yeast,” is a common culprit for ear infections. Skin infections, whether caused by bacteria or yeast, will often be associated with redness, swelling, skin lesions such as pustules and scabs, colored discharge, and a foul odor.
Several factors may lead to a skin infection. Trauma or injury to the skin (including burns, bites, self-trauma from scratching, etc.) is a common way for an infection to arise. Dogs with immune-mediated diseases or those with impaired immune systems may be more prone to skin infections. Breed dispositions, anatomy, and genetics may also play a role. Finally, underlying allergies and chronic itching often lead to chronic and recurrent secondary skin infections.
Ringworm (Dermatophytosis)
Ringworm (also known as Dermatophytosis) is caused by a group of fungi known as dermatophytes and is not a worm at all! This type of infection is much more common in cats but is another potential cause of scratching in dogs. In dogs, ringworm can cause itchy lesions with circular areas of hair loss, where the underlying skin may be red or have small scabs.
Hormonal (Endocrine) Skin Diseases
Underlying medical conditions such as hypothyroidism (an auto-immune disease that causes decreased thyroid hormone production) and hyperadrenocorticism (i.e. Cushing’s Disease; a disease of excess steroid production by the adrenal glands) are not primary causes of itching in dogs; however, these conditions result in increased susceptibility to developing skin infections that then cause your dog to scratch.
Breed Predisposition
Some breeds of dogs may be more prone to causes of itching and require extra care and consideration to maintain healthy skin. Cocker Spaniels, Golden Retrievers, and English Bulldogs are a few examples that are known to be more susceptible to ear and skin infections. Regularly cleaning the ears and skin folds in these breeds can help prevent infections that may lead to scratching and discomfort. Pitbulls have been anecdotally linked to having a higher chance of developing food and environmental allergies, though the underlying reason for this is not well understood.
Ectoparasites and Their Impact
Several types of skin parasites, or ectoparasites, can cause your dog to itch. Fleas, mites, and lice are three common ectoparasites that can invade the skin and hair of dogs and cause moderate to severe itching. While fleas and lice are visible to the naked eye, mites (including Demodex and Sarcoptes) can only be identified under a microscope.
Fleas and flea bite allergy: These small parasites feed on a dog’s blood and may cause itching, hair loss, and secondary skin infections. Some dogs can also develop an allergy or “hypersensitivity” to flea bites (specifically, flea saliva), known as flea allergy dermatitis. While most dogs will exhibit some degree of scratching as a result of fleas, these dogs have a more significant reaction leading to intense itching.
Mange mites: The two most common types of skin mites in dogs are Demodex and Sarcoptes, which are sometimes referred to as Demodectic Mange (“red mange”) or Sarcoptic Mange (“scabies”). Demodex are mites that live inside or near the hair follicle, while Sarcoptes are a burrowing mite that go deeper into the skin. Both can cause itching; however, intense itching is more commonly seen with Sarcoptic Mange. Dogs naturally have small numbers of Demodex on the skin, but infection and clinical signs arise when the infestation becomes too great, usually in animals that are young or immunocompromised.
Lice: The final type of ectoparasite that can cause itching in dogs is lice. Luckily, lice are host-specific, meaning lice on your dog cannot be passed to other species or people living in the home. Unlike fleas, lice do not survive off of their host for more than a few days, making treatment of the dog and environment relatively straightforward. Lice are visible to the naked eye, can often be seen moving, and are pale in color. While lice can lead to itching and scratching in your dog, they do not tend to cause significant damage to the skin or other issues.
Allergic Reactions in Dogs
Allergies are a common cause of dog itching when no fleas or other ectoparasites have been identified. Allergies in dogs are often divided into two categories – food allergies and environmental allergies (also known as atopy or atopic dermatitis).
Food allergies can lead to itching when a dog is allergic to something in their diet, usually a protein source. Environmental allergies are caused by something in the environment, such as pollen. It is not uncommon for dogs to be allergic to more than one thing.
They can lead to scratching, redness, and recurrent skin and ear infections as a result of an immune-mediated and inflammatory response to an allergen. Food allergies may also cause gastrointestinal issues in some cases, while environmental allergies may have a seasonal component. For more information on dog allergies and treatment options, visit our page “Dog Allergies: All You Need to Know From Symptoms to Treatment.”
Infections: Bacteria vs. Yeast
Infections caused by bacteria or yeast are another common cause of scratching.
While small amounts of bacteria and yeast are naturally present on the skin of dogs, an overproduction of either can lead to infection. Skin infections can cause pain, discomfort, and itching in dogs. Malassezia, a type of “budding yeast,” is a common culprit for ear infections. Skin infections, whether caused by bacteria or yeast, will often be associated with redness, swelling, skin lesions such as pustules and scabs, colored discharge, and a foul odor.
Several factors may lead to a skin infection. Trauma or injury to the skin (including burns, bites, self-trauma from scratching, etc.) is a common way for an infection to arise. Dogs with immune-mediated diseases or those with impaired immune systems may be more prone to skin infections. Breed dispositions, anatomy, and genetics may also play a role. Finally, underlying allergies and chronic itching often lead to chronic and recurrent secondary skin infections.
Ringworm and Its Effects
Ringworm (also known as Dermatophytosis) is caused by a group of fungi known as dermatophytes and is not a worm at all! This type of infection is much more common in cats but is another potential cause of scratching in dogs.
In dogs, ringworm can cause itchy lesions with circular areas of hair loss, where the underlying skin may be red or have small scabs.
Hormonal Skin Diseases
Underlying medical conditions such as hypothyroidism (an auto-immune disease that causes decreased thyroid hormone production) and hyperadrenocorticism (i.e. Cushing’s Disease; a disease of excess steroid production by the adrenal glands) are not primary causes of itching in dogs; however, these conditions result in increased susceptibility to developing skin infections that then cause your dog to scratch.
Diagnosis and Treatment of Itching
Because there are many causes of itching in dogs, and many of those causes result in lesions (abnormal areas of tissue) that appear very similar, diagnosing the underlying cause may require multiple diagnostic tests.
First and foremost, however, your veterinarian will obtain a thorough medical history and perform a physical exam on your dog. This can provide invaluable clues as to the cause of itching and can also aid in excluding some causes of itch. A detailed patient history includes answers to questions such as the age of onset, areas of the skin that are affected, living environment, what time of year the condition is worse (i.e. seasonality), past and current diets, current medications, coexisting medical conditions, the severity of the itching (pruritus scale), and prior diagnostics, treatments, and responses to those treatments.
Following a detailed medical history and exam, your veterinarian may perform one or more of these diagnostic tests:
- Cytology (sample of skin or ears) is viewed under a microscope to determine the presence of yeast or bacteria.
- Skin scrapings (superficial or deep) are also viewed under a microscope to demonstrate the presence of mange mites such as Demodex or Sarcoptes.
- Flea combing and tape impressions are helpful in the diagnosis of parasites such as fleas and lice.
- Aggressive flea control should be implemented in all itchy dogs even if fleas are not identified. In flea-allergic dogs, even the bite of a single flea can cause a significant reaction.
- Wood’s lamp examination (certain strains of ringworm will fluoresce an apple green color when viewed with this ultraviolet light), trichogram (examination of plucked hairs under the microscope to look for fungal spores and hyphae), and fungal cultures may be warranted if dermatophytosis (ringworm) is suspected.
- Culture and sensitivity testing should be considered in the case of repeat or non-responsive bacterial skin infections to determine the causative bacteria and the antibiotics that will be most effective.
- An elimination diet trial is required to diagnose a food allergy. This involves feeding a prescription hydrolyzed, limited ingredient, or novel protein diet for a minimum of two to three months.
- Allergy testing utilizing skin or blood tests may be recommended if an owner wishes to identify allergens or is interested in pursuing allergen-specific immunotherapy. Allergy tests using hair samples or saliva have not yet been shown to be accurate or helpful.
- Bloodwork may be recommended to check for underlying conditions such as hypothyroidism and hyperadrenocorticism that could contribute to itching in your dog.
- Skin biopsy is indicated for those patients with minimal response to treatment or non-typical lesions, as may often be the case with some types of skin cancers.
- Referral to a veterinary dermatologist is always an option, especially for more complex cases.
Final Thoughts on Itching in Dogs
While excessive itching and scratching can be incredibly frustrating for you as an owner and cause significant discomfort for your dog, there are many options available to help prevent and treat the common causes discussed above.
Remember, obtaining a proper diagnosis of the underlying cause is very important when it comes to getting itch relief for your pet, especially if the problem is severe and does not seem to be resolving.
FAQ – Frequently Asked Questions about Itching in Dogs
What should I do if I suspect my dog has fleas or lice?
If you see or suspect fleas or lice, consult your veterinarian for a prescription preventive and guidance on cleaning your home. Year-round prevention is recommended.
How can I help my dog at home if it is itching?
You can try supplements like Omega-3 Fatty Acids or probiotics to support skin health. Bathing with an anti-itch shampoo may also help, but avoid over-bathing.
Can changing my dog’s diet help with itching?
Yes, if a food allergy is suspected, try a hypoallergenic diet for at least three months to see if symptoms improve.
Is Benadryl effective for my dog’s itching?
Benadryl can help with minor allergic reactions, but it is not a long-term solution for chronic itching. Always consult your veterinarian before administering.
How often can I give my dog Benadryl for itching?
Benadryl can be given every 8 to 12 hours for mild allergic reactions, but consult your veterinarian for the appropriate dosage based on your dog’s weight.
When should I take my dog to the vet for itching?
If your dog’s itching is excessive, persistent, or accompanied by signs of a skin infection, such as lesions or discharge, it’s time to see a veterinarian.
