An itchy pet can be frustrating for both the owner and the pet.

I rescued a particularly itchy cat who had scratched herself until she bled. Her owners ended up abandoning her at the dermatologist’s office. I took her home and managed her pruritus (medical term for itchiness) which was likely due to allergies and obsessive compulsive behavior. I won’t judge her previous owner’s reasons for abandoning her. Pruritus can be frustrating and expensive to treat. No doubt, many pets end up in the shelter due to unmanageable itchiness. But, if you know the correct way to approach it, you will end up saving time and money.

I had a client bring in her nearly hairless dog, who’s skin was red and bleeding in areas from severe itching. She had tried everything, she said… except seeing a veterinarian. This dog had been treated with coconut oil, raw food, diatomaceous earth, itchy dog supplements, homeopathy, benadryl, Vetricyn (which is basically diluted bleach)… Nothing worked. After the severe the pyoderma (skin infection) and underlying allergies were taken care of, the dog was like a new puppy again.

Don’t become a victim of fancy marketing schemes and sales people. Many companies have come out with a variety of products directed to itchy pets. The problem is, if you don’t know why your pet is itching, these products may only have limited benefit. Many of the products on the market don’t work at all (if they do “work” it is likely your pet’s itchiness went away on its own). This is because Itchiness isn’t a disease in itself. Sometimes, it may appear that your pet becomes less itchy on a particular product for a while and then it stops working, and you have to find something else, because the underlying cause of the itching has not been addressed.

How To Find Out Why Your Pet Is Scratching

Common causes of scratching include ectoparasites (fleas, lice, mites etc…), bacterial or fungal infections and allergies. In order to determine what is the cause, your veterinarian will look carefully at your pet’s coat and then likely take some samples of the hair and skin and look under the microscope to look for mites, bacteria or yeast. Sometimes, samples will have to be sent to the laboratory for culture or histopathology.

Possible Diagnosis And Treatment Options

A dog with demodex, from http://www.leicesterskinvet.com

Demodex Mites

This is a common problem in young dogs, but can be a problem in older dogs as well. In healthy dogs, small numbers of D. canis mites are normal in dogs, but large numbers causing itching and hairless is abnormal. There is likely a genetic or immunological cause of this disease, as it is a common disease in Shar peis, Pit Bulls, Boston Terriers, English Bulldogs, West Highland Terriers, Old English Sheepdogs and German shorthaired pointers. Because of this genetic predisposition, any dog with demodicosis should not be bred. These mites are not considered contagious.

In the past, demodex was treated with ivermectin daily. However, this treatment often lead to side effects and it took a long time to treat the condition. Now, new products to help protect against fleas, Nexgard and Bravecto, are shown to be very effective in treating demodex, they don’t require daily administration, and have become the treatment of choice due to their safety and efficacy.

This is a dog I treated for ivermectin toxicity. Slinky was being treated with ivermectin for demodex. He started showing signs of toxicity and was not improving. I treated him with intralipid and he made a fantastic recovery.

This is a pit bull puppy with a common presentation of demodex.

There may likely be a secondary skin infection (pyoderma) due to the demodex infestation, so your veterinarian may also prescribe antibiotics and/or a prescription shampoo to help treat the infection. Omega 3 fatty acid supplement is also recommended to help bring down the inflammation and improve the lipid barrier of the skin to prevent drying.

Fleas

“But my pet doesn’t have fleas!” Veterinarians hear this all the time. Don’t worry, its not a reflection of you if your pet has fleas. They are the most common ectoparasite of dogs and cats. If your pet is not on a *good* flea prevention regularly, and is itching, we have to make sure that the itching is not coming from flea allergy dermatitis.

All it takes, is for one flea to jump on and bite your pet, and your pet will be scratching for weeks. Pets who are allergic to fleas are reacting to their saliva. Therefore, just because you have not seen a flea, does not mean that a flea was not the cause of your pet’s scratching. That is why, all itchy pets need to be on a good flea control.

“But my pet is on flea prevention!” What kind? If it is Advantage, Frontline, other store-brand, a flea collar you bought at the pet store, then likely your flea control is not enough. We are finding many of these products are just not as effective as the newer products coming out. I really like Comfortis (cats & dogs), Nexgard (dogs) and Bravecto (dogs).

For cats, Comfortis is the best flea prevention. It is an oral tablet you give once a month. Some may find it difficult to give cat's pills, see the video below for one great technique. If you ultimately cannot give your cat a pill, Cheristin is a topical flea prevention that you apply once a month that is almost as good as Comfortis.

A common presentation of flea allergy dermatitis. Notice the redness and hair-loss on the back, near the tail.

Additionally, Capstar (dogs & cats) is another good product that gets rid of fleas fast, but unfortunately, in order to really be effective, you have to give it daily in flea allergic pets.

If your pet is scratching, we have to make sure that fleas are not the culprit, so no matter what, we have to make sure your pet is on a good flea control at an appropriate interval.

Pets can get tapeworms (Dipylidium caninum) from fleas. Animals (and people) become infected with tapeworms when they ingest an infected flea.

Fleas are also involved in Cat Scratch Disease (CSD). Cat Scratch Disease is caused by Bartonella henselae which is ingested by fleas that drink infected cat blood. Live Bartonella henselae are passed in flea poop. Claws of cats contaminated with flea poop then scratch humans, and as a result, over 22,000 cases of Cat Scratch Disease are reported every year.

Other Ectoparasites

Scabies and lice are other common causes of scratching in dogs and cats. Your veterinarian will be able to determine if this is the cause by looking at hair pluck samples and skin scrapings under a microscope. Appropriate treatment will depend on what kind of ectoparasite they find.

Microscopic image of Sarcoptes scabiei — Microscopic image of *Sarcoptes scabiei*

Food Allergy Dermatitis- How to diagnose and treat

“But, my pet has been on that food his whole life, and its an expensive high quality grain-free food!” Food Allergy Dermatitis is developed over time to common proteins in your pet’s food. The most common food allergies are to chicken, beef, soy, egg, or dairy. Sometimes an allergy develops to a carbohydrate or rarely a preservative. These animals are itchy year-round and may have signs of stomach upset as well such as vomiting, diarrhea or flatulence. Animals usually rub their faces or chew at their feet and are prone to skin and ear infections.

Signs of food allergies will continue as long as the pet is fed the offending protein, and signs will continue for several weeks after the offending protein is finally removed.

Unfortunately, despite what many companies will try to sell you, there are no reliable skin or blood tests available to determine what food your pet is allergic to. The only way to determine for certain what your pet is allergic to is to do an elimination diet trial.

During the diet trial your pet will be fed a homemade or commercial diet that contains a protein and carbohydrate your pet has never been exposed to. These diets contain novel proteins such as kangaroo, rabbit or venison among others. As an alternative, there are “low molecular weight” diets available that contain common proteins such as chicken or beef, but the proteins have been hydrolyzed down to a small size that the immune system is thought not to react to. However, some pets that are very sensitive may react to these hydrolyzed diets too. Unfortunately, nowadays, pet stores sell so many different varieties of food that contain venison, rabbit, lamb etc… and many people offer all of these foods to their pets to give them some variety, and in that case, the pets have developed an allergy to all these proteins and an elimination diet is difficult in this case.

To make matters worse, reports have shown that even when a pet owner goes to a board certified veterinary dermatologist, there is only about a 5% owner compliance rate. This is because in order to complete a successful diet trial, the pet has to go at least 8-10 weeks ingesting nothing except for the novel diet. This means no treats, flavored toothpaste, medications, chew toys, pig ears, flavored vitamins or flavored heartworm prevention. You have to pretend the allergy is as severe as a peanut allergy, and anything other than the novel diet is a peanut! Then, you will re-check with your veterinarian and discuss whether or not the itching has decreased.

In order to prove a food allergy, you have to introduce the original diet back to the pet. This is known as a “diet challenge.” The scratching and other clinical signs will return within hours or days if the diet is really the cause. Then you can go back to the diet that worked!

Unfortunately, these pets with food allergies likely have other allergies as well. Dermatologists refer to this as an “allergic personality.” So even though you have discovered that food causes some or most of their itching, they may likely also have flea allergy, allergy to pollens, molds, dust etc… Therefore, they need to be kept on a strict, high quality flea control and be monitored closely for skin infections.

During the diet trial, it is important to keep a log of any changes that you notice such as appetite, bathroom habits, scratching, redness of ears or skin or changes in weight. Practice keeping a daily log and rate the level of itchiness on a scale of 1-10, with 10 being constant itching.

Atopic Dermatitis

Pets with Atopic Dermatitis (AD) are allergic to a variety of things in their environment including pollens, molds, yeast, dust etc… They have itchy ears, itchy feet, and dogs may get recurrent “hot spots” they will lick until they are raw. Unfortunately, there is no diagnostic test for atopic dermatitis. Diagnosis is made based on history, clinical signs and ruling out, or making sure that other conditions such as flea allergy (or other ectoparasites) and food allergy are not the cause. Pets usually develop AD after 1.5 years of age.

Your veterinarian will likely take some samples from your pet’s ears, skin or feet to look for signs of secondary bacterial or yeast infection. This is because pets with Atopic Dermatitis have defects in their epidermal and lipid skin barrier that makes them susceptible to secondary skin and ear infections.

Breed predispositions

Boxer, Bull Terrier, Cairn terrier, Chow Chow, Cocker spaniel, French bulldog, Fox terrier, German shepherd dog, Golden retriever, Irish setter, Labrador retriever, Poodle, Rhodesian ridgeback, Shar-pei, Viszla and West Highland White terrier, Bichon Frise, Cavalier King Charles spaniel, Jack Russell terrier, Great Dane, and Silky Terrier

Treatment

There is no one quick fix for AD. A treatment plan is developed working with your veterinarian and carefully considering your pet’s clinical signs. Pets may have periodic or seasonal flare ups of skin and ear infections that require oral antibiotics or antifungals, prescription antibacterial or anti fungal shampoos or sprays. Avoid “over the counter” shampoos and sprays unless you consult your veterinarian. Many over the counter products can actually make itching worse. Omega 3 fatty acid supplementation can decrease the inflammation of the skin and prevent drying. Antihistamines can help some as well, but may not help much in a severe flare up.

Allergen-specific immunotherapy- this involves subcutaneous injections of small amounts of allergens given at home or in the veterinary office. You start off giving low amounts of allergen and gradually increasing to larger amounts. Adjustments are made based on the pet’s response. Studies have shown immunotherapy shows greater than 50% improvement in allergen treated dogs over placebo. This is a very safe treatment that does not require bloodwork monitoring. The downside is that it can take up to 9 months to be fully effective.

http://veterinarymedicine.dvm360.com/allergen-specific-immunotherapy-canine-atopic-dermatitis-making-it-work

If you are concerned about giving injections, now there is sublingual immunotherapy available (http://veterinarynews.dvm360.com/using-sublingual-immunotherapy-treat-atopic-dermatitis-canine-veterinary-patients). However, if your pet is not improving after 8 months, you may have to switch to an injectable immunotherapy.

Medications

Apoquel (oclacitinib) - This is a new medication that has shown to be successful in 66% of treated dogs. It is a janus kinase inhibitor, which means it inhibits a signalling pathway that results in itching and inflammation. (https://www.zoetisus.com/bmst-minisite-apoquel/index.aspx) (http://veterinarynews.dvm360.com/apoquel-qa-will-oclacitinib-revolutionize-treatment-allergic-dermatitis)

Atopica (cyclosporine) - This medication was approved for use by the FDA in 2003 for treatment of atopic dermatitis. It has undergone extensive testing and has been shown to block the release of inflammatory cytokines and histamines. Atopica is an oral pill or liquid that can be given to both dogs and cats. Many respond very well to it and side effects are rare. Some pets may vomit on the drug, so it is best given with a meal. Atopica takes 4-6 weeks of daily therapy to start working, but often you can decrease the administration to every 2-3 days long term.

Glucocorticoids - These include steroids such as prednisone or prednisolone. This is an older medication, and may be given by your veterinarian as a trial to see how your pet responds, but it may not be a good idea to have your pet on glucocorticoids long term. It is best used as a trial or on an as needed basis, and then you can transition to the newer medications such as Atopica or Apoquel.

Sometimes veterinarians give a long acting steroid shot so you don’t have to give oral medications every day. However, this is a more risky approach than medicating with oral pills daily, because once you inject it, you can not take it back if the pet responds poorly to it. Long term use of glucocorticoids can have side effects such as liver problems, skin infections, urinary infections and gastrointestinal ulceration. If the itching is due to a mites or ringworm, the skin condition can worsen.

Managing Flare Ups

It is important to keep your veterinarian apprised of how your pet is doing. If you can, keep a journal, and if you notice the itching has worsened, let your veterinarian know and they can adjust the treatment to best suit your pet. These pets are susceptible to recurrent skin infections and these have to be diagnosed and managed. Antibiotics that have worked in the past may no longer work if your pet has developed a resistant skin infection. A culture of your pet’s skin may need to be performed in order to determine the best choice of antibiotic for your pet.

Skin Infection (Pyoderma)

Pyoderma, which means “pus in the skin,” usually presents as a rash, red inflamed skin, pustules that look like “zits,” or epidermal collarettes which are circular ares with scales around the edges. Chronic skin infections cause thickened and dark pigmented skin.

Skin infections are common in dogs with allergies or external parasites, but can also be caused by internal diseases. Diagnosis is based on physical exam findings as well as samples of the skin that is looked at under a microscope. Sometimes a skin biopsy and blood work may be needed to rule out other diseases and identify an underlying cause.

Treatment often involves a combination of oral and topical antibiotics will be given and treatment for deep skin infections may take several weeks or months to treat. Oral antibiotics should always be given with food (unless otherwise indicated) for prevent gastro-intestinal upset. Common side effects include vomiting, diarrhea and loss of appetite. If you notice any GI upset, stop the medication and contact your veterinarian. Once appetite and GI signs return to normal you may try the treatment again after a meal. If antibiotics that have worked in the past appear to not be working, contact your veterinarian, there may be a new or resistant infection forming. Even if the skin is looking better, it is important to complete the full course of antibiotics because the infection may still be present.

Yeast Infection (Malassezia pachydermatis)

Yeasts are spore-like forms of fungi and Malassezia dermatitis is a fungal infection of the skin. Skin yeast infections are very itchy, crusty and smelly. Many dogs are also allergic to the yeast on their skin, which worsens the condition.

How do dogs get yeast infections? Yeast on the skin is normal in small numbers. However, increases in skin oils (from allergic flare ups), immune disease and seborrhea (excess oil production in the skin) predispose to yeast infection.

How does your veterinarian diagnose yeast infection?

Looking at a smear of the skin under a microscope is one of the most common ways of diagnosing a yeast infection.

Treatment

Based on your pet's condition, anti-fungal medications and shampoos will likely be prescribed. But, your pet will likely get recurring yeast infections unless the underlying cause (such as allergies) is diagnosed and treated appropriately. Usually, several weeks of anti-fungal treatments are required. Animals will be bathed twice a week and the prescription shampoo will be left on for 10-15 minutes before rinsing.

Breed Predispositions

West Highland White Terrier, Basset hound, Cocker spaniel, Silky terrier, Australian terrier, Maltese, Chihuahua, Poodle, Shetland sheepdog, Lhasa apso, and Dachshund.

Psychogenic Alopecia or Overgrooming

For some cats, obsessively grooming can be a manifestation of some underlying anxiety. Diminishing stressors from other pets, and people is critical. You can also try Feliway, a feline pheromone that helps relieve stress as well as medications such as amitriptyline. These cats also need to be on a good flea prevention as well.

Conclusion

Don’t be a victim of pet store sales people and fancy internet adds marketing cures for dog itching. Those supplements and homeopathic remedies will just waste your time and money. Itching has a variety of different causes and a systematic approach to diagnosing and treating the condition is what is needed for the best results.