Itching is one of the most common presenting problems for the general practicing veterinarian. For some, these episodes are short & infrequent, but many other pets suffer with constant discomfort. Let’s try to tackle some common questions about this scratchy subject in the first of our 2-part series.

“If the itching is caused by allergies, what exactly is my pet allergic to?”

There are three main types of allergic dermatitis that cause itch: Flea allergy dermatitis, environmental allergies (atopy), and food allergies. One kind may predominate in any given animal, but many patients have combination allergies.

The distribution of skin lesions on the animal’s body is helpful. Fleas like the lower back, but atopy and food allergies usually affect the face/ears, feet, belly & rear end.

Age of onset, the degree of response to steroids, and seasonality are also considered.

Seasonality can be challenging to determine in climates like Central Ohio, where seasons are ambiguous.

Additionally, many of the problematic allergens are indoors, like storage mites & mold. Allergy testing can be helpful but is generally done to design an allergy serum/vaccine for an animal with highly suspected atopy. There are no recognized valid laboratory tests to determine food allergies.

“How can fleas be making my pet itch when I don’t see any? Why isn’t anyone else in the house being bitten?”

Not every pet has the same level of allergic reaction to a flea bite. But in a highly sensitive animal, a SINGLE flea bite can cause itching for weeks! Many pets can groom away almost all evidence of a flea problem. This is especially true for cats. Fleas have four different life stages, with the adult being the only one visible without a microscope. Those adults are doing all the biting, but only represent ~5% of the total population in an animal’s environment.

Since dogs & cats have higher core body temperatures than humans, fleas will preferentially bite them. Immaculate flea prevention for all animals in the home is imperative to prevent infestation and control itching.

“How about the flea prevention products I see at the pet/grocery store?”

Consistent use of a high-quality flea preventative is recommended for any pet experiencing episodes of itching. Over-the-counter products may be less expensive, but they often have reduced safety & efficacy. Proper flea control can be one of the least expensive ways to reduce itching in an allergic pet.

“If my pet’s itching always improves on steroids & antibiotics, why can’t they just stay on them?”

Steroids are very effective in controlling allergic itch and inflammation. They are a valuable tool in the management of allergies. But long-term dependence on steroids should be avoided if possible. Side effects can be inconvenient, dangerous and are numerous. These include increased thirst, hunger & urination, panting, behavior changes, decreased skin & hair coat quality, muscle atrophy, obesity, increased infections, and poor wound healing.

Antibiotics are often necessary to address secondary skin infections in allergy patients. But overuse can lead to resistance, where bacteria develop the ability to survive the drugs meant to kill them. Infections then become increasingly difficult to treat. Antibiotics can also destroy ‘friendly’ bacteria in the gut that aid in digestion, causing diarrhea.

There are several alternatives for long-term management of allergies, including Cytopoint injections, Apoquel, Atopica, topical products, hypoallergenic foods, and allergen-specific immunotherapy.

“How could my pet be allergic to the food they have been eating for years without a problem?”

As proteins & other substances in the diet are broken down in the gastrointestinal tract, they can become allergens. A cascade of inflammation ensues, and the skin is the main target. This process takes time, so many pets have been eating the offending food for years.

“I’m ready to consider a diet trial. How do we do this?”

Feeding a hypoallergenic diet is the ONLY way to determine if a pet has food allergies. Blood or saliva tests are not accurate, nor recommended.

Many diets targeting skin sensitivities are found at your local pet store. However, they are not manufactured to the same strict standards as prescription diets and are not recommended for a true dietary trial. Prescription options include novel or hydrolyzed protein foods.

Another challenge is ensuring all family members comply with feeding ONLY the special diet for a 2–3-month trial period. It can be tough to negotiate this commitment, but exclusivity is required for the best outcome.

“What about antihistamines, like Benadryl, Zyrtec or Claritin?”

Antihistamines are a popular and affordable category of medication. Histamine is a major mediator of inflammation in people, but considerably less so in animals. Antihistamine receptors are inconsistent across the canine species, so it may be necessary to trial several ones sequentially. Sedation is a common side effect. Antihistamines rarely provide lasting relief when used alone but may be helpful in combination with other therapies.

A Success Story

Lightning is a 7-year-old Domestic Shorthair cat who struggled with persistent & intense itching, especially around her face and ears. Continual self-trauma was resulting in redness, hair thinning, scratches, and secondary skin infections.

Temporary response to steroids & antibiotics was seen, and her owner was using a prescription flea medication every month. We needed to find a long-term solution for her! Her itching did seem to follow a seasonal pattern, so her suspected diagnosis was atopy, or environmental allergies. Daily dosing of Atopica liquid was started. Within three weeks, Lightning’s condition had dramatically improved. She & her owners were finally able to sleep through the night!

Lightning now takes her Atopica only 2-3 times a week, and her itching is still under control. This means long-term management is both easy and affordable for her family.

Check out her before and after photos!