A healthy dog scratches himself so little that you don’t even really notice it, and he certainly doesn’t spend time biting or licking his coat. More than a few seconds of scratching here or there over the course of a day (or rolling against a surface to relieve itchiness), and there’s a good chance something is wrong.
Unfortunately, something is wrong relatively often. Excessive scratching, biting, licking, chewing, or rolling due to itchiness, medically known as pruritus, is one of the most common reasons people seek veterinary care for their dogs, according to the American Animal Hospital Association (AAHA).
The cause is generally an allergy, but what kind can be tricky to figure out, in no small part because an allergy diagnosis does not come until after ruling out other itchy diseases. The dog remains miserably uncomfortable in the meantime. His skin can become not only itchy but also inflamed or pimply-looking and crusty. And in literally assaulting his skin with his mouth to try to relieve the discomfort, he can create significant damage. That leaves the dog open to infiltration of bacteria that can cause infections on top of the allergy — a misery two-fer.
To help facilitate diagnosis and treatment of an itchy dog, the AAHA has developed a new set of guidelines for managing allergic skin diseases in our pets. Here’s what you need to know.
The initial exam
You can reasonably expect the following at your dog’s first visit to the doctor to try to determine the cause of the itching.
1. Flea combing. Flea allergy dermatitis is one of the most common allergic skin diseases in dogs. For that reason, the AAHA guidelines say that flea combing by the veterinarian is a crucial part of the examination (although if nothing is collected with the combing it does not rule out a flea allergy — sometimes it takes more sleuthing). If your dog does have fleas, it doesn’t mean you keep a dirty home. Fleas happen. In allergic dogs, typically just a few flea bites can be enough to trigger an itch. General recommendations include yearround flea control, even in cold weather.
2. Ear exam. An outer ear infection, medically termed otitis externa, can go hand in hand with a canine skin allergy. You can expect that the vet will check your dog’s ears.
3. Prescription to control the itching. Your dog should be given a drug to make him less itchy right away. It can take a while to nail down the cause, particularly in the relatively rare case of an allergy to a food, and your pet does not need to be in discomfort and ripping into his skin during the diagnostic period. Dogs often respond quickly to glucocorticoids, namely prednisolone, methylprednisolone, or dexamethasone. Oclacitinib (Apoquel) and lokivetmab (Cytopoint) are also commonly prescribed to abate the itch. Cyclosporine and immunotherapy (allergy vaccines) do not provide immediate relief. They can take several weeks to kick in (but can prove effective for long-term treatment). Antihistamines are usually not prescribed at all as they’re not effective for an allergic itch.
4. Cytology to check for secondary infection. If harmful bacteria have entered your dog’s body because of an ulceration in the skin resulting from the excessive scratching and licking, cytology will help find it. A cytological exam is conducted by pressing a dog’s coat to some Scotch tape or a glass slide, staining the sample, and putting it under a microscope to help identify the harmful pathogens. That way, the correct antibiotic or, very commonly, shampoo can be prescribed. (Sometimes the itching will not subside until the secondary infection is vanquished.)
5. Skin scraping. The vet will use a scalpel to collect and examine debris, hairs, and cells from the top layer of skin and then look via microscope at what has been collected. That will help the doctor understand better if mites or other parasites are causing the problem. But as with flea combing, a negative result does not exclude completely the possibility that parasites are causing a problem; your vet may still recommend a preventive. If not, the culprit could be an environmental allergen or, in less common instances, a food allergy.
Your vet may also ask a number of questions, including whether the itching is seasonal, whether other pets in your home feel itchy, whether you regularly give your dog a flea preventative, and whether your dog has recently come in contact with stray dogs or dogs at a boarding facility. Answers to these questions can help determine what’s going on.
But for all that, it can sometimes take two to four months or even longer to figure out the specific problem and find the right combination of treatments. The AAHA suggests that if adequate control of symptoms cannot be achieved by the third visit to your primary care vet, referral to a veterinary dermatologist should be presented to you as an option.
It’s a situation that requires a “communication-rich approach” with the vet to arrive at a solution for your pet’s condition, says the AAHA. In most cases that solution will probably involve a lifetime of ongoing treatment to have good control of the allergy and avoid relapses. But with patience and leaving no stone unturned, your dog should be restored to a state of comfort and relief from what can be incessant, exasperating itchiness.
