Dermatology: Dealing With Itchy Patients


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Clinical practice guidelines from the International Task Force on Canine Atopic Dermatitis have gotten a lot of interest from primary care veterinarians.

These guidelines, created by veterinary dermatologists, offer recommendations to help primary care practitioners identify and treat chronic atopic dermatitis (AD).

Last June, the World Small Animal Veterinary Association endorsed the amended guidelines, which have since been translated from English into 18 additional languages.

Thierry Olivry, DrVet, Ph.D., Dipl. ECVD, Dipl. ACVD, led the international task force. He is with the Department of Clinical Sciences and the Center for Comparative Medicine and Translational Research in the College of Veterinary Medicine at North Carolina State University in Raleigh. Dr. Olivry says the team concluded that treatment of canine atopic dermatitis must be individualized for each patient.

“Treatment regimens depend on the canine patient, if acute flares or chronic skin lesions of AD are presented and whether signs are localized or generalized,” Olivry says. “Chronic canine AD is a challenge and known flare factors, including food, flea and environmental allergens, Staphylococcus bacteria and Malassezia yeast, should be investigated before moving forward with a treatment plan.

“In addition, optimization of skin care, reduction of skin lesions and pruritus and prevention of recurrence of signs after remission are a treatment goal,” Olivry adds.

Evidence-based medicine principles were highlighted in the guidelines, Olivry says, but consideration for owners’ finances and convenience must be considered in efforts to have a substantial compliance rate.

The task force defines canine atopic dermatitis as a genetically predisposed inflammatory and pruritic skin disease with characteristic clinical features associated with IgE antibodies, most commonly directed against environmental allergens. However, experts also include information on a parallel condition—atopic-like dermatitis (ALD), which must be differentiated from AD.

“Patients with ALD have the same clinical signs as those with AD, but in ALD, an IgE response to environmental or other allergens cannot be documented by usual methods,” Olivry says. “Dermatological issues, especially ones proven to be chronic, can be very frustrating to figure out and there is a point when vets will want to refer to a specialist.”

Olivry says that while the most prevalent skin conditions and contributing factors tend to differ from one region to another, they can be vastly different between practices in the same state.

Common is variable

“In dogs, fleas (with geographical variations; e.g. in Colorado fleas are rare), ear infections and allergies are the most common factors contributing to itchy skin,” says Patrick Hensel, Dr.med.vet., Dipl. ACVD, who is an associate professor of veterinary dermatology  at the College of Veterinary Medicine at the University of Georgia in Athens.

“Cats also have a lot of skin issues from flea infestations, dermatophytosis, and allergies,” Hensel continues. “If a pet doesn’t appear to have a life-threatening problem, owners don't always immediately seek medical attention. However, the animals are suffering, and based on the degree of pruritus and self-trauma, it can have an impact on the animal’s quality of life.”

Karen Helton-Rhodes, DVM, Dipl ACVD, owner of Riverdale Veterinary Dermatology in Riverdale, N.J., says flea allergy dermatitis is rarely seen at her Northeast office because area veterinarians do an excellent job of recommending flea control.

“Southern states may have more problematic flea hypersensitivity cases that need specialist intervention,”  Helton-Rhodes says. “In my practice, canine allergic dermatitis, bacterial folliculitis and otitis externa are common. In feline patients, pruritic dermatitis, eosinophilic granuloma, pemphigus foliaceus, and otic polyps with secondary infection are common.

“Otitis cases can have a multifactorial etiology,” she continues. “Each case is unique regarding specific etiology as well as the complicating infectious agent. Feline otitis cases are often associated with inflammatory polyps or apocrine gland cystadenomas, while canine cases frequently have an allergic etiology.”

Sandra N. Koch, DVM, M.S., Dipl. ACVD, assistant clinical professor at the Veterinary Medical Center at University of Minnesota in Minneapolis, says her Central U.S. office treats a large number of canine food and environmental allergies.

“After canine allergies, we see otitis externa and demodicosis,” Dr. Koch says. “In cats, we see allergies (mainly flea, food and environmental allergies), dermatophytosis and ear mites.”

When a pet is constantly itching, it’s difficult to ignore the symptoms, experts say. But even if a problem is noted, it isn’t always addressed with a veterinary visit. The first stop is typically the primary care veterinarian—but by this time the “itchy area” has been licked, scratched and chewed on, probably creating additional problems.

Often pet owners expect the issue to be diagnosed, treated and cured in a single visit. They may push for what they perceive as a quick-fix to the problem.

“Unfortunately, most owners have become used to the instant and cheap relief provided by steroids given to the dog or cat either orally or through infection,” says Keith Hnilica, DVM, M.S., MBA, Dipl. ACVD, of the Knoxville Veterinary Referral Group Pet Wellness Center Allergy and Dermatology Clinic in Knoxville, Tenn. “We have made great progress in treating arthritis without the masking magic of steroids, but most owners are unaware that the allergic disease can be controlled and the infection prevented without steroids and all of their adverse effects.”

Once treatment results occur, owners think their work is done, but dermatologists say more often than not, their treatment is for management, not cure, of dermatological conditions.

“Most owners fall into the trap of thinking that the infection is the problem, which is logical from their perspective because when the infections are treated (ear or skin, yeast or bacteria) the itching and skin rash improve,” Hnilica says. “However, the actual allergy is the cause of the infections and often, easy and inexpensive treatments work well.”

Chronic versus compliance

Helton-Rhodes says client frustration from unsuccessful, ongoing treatment with a primary care veterinarian often leads to solicitation of third-party advice.

“Frustrated clients search for resolution on the Internet or from local breeders which can, at times, lead to confusion,” Helton-Rhodes says. “Most clients are happy to consider a specialist to help speed recovery.”

Client education must be incorporated when a diagnosis is made.

“We are dealing with many chronic and recurrent diseases (e.g. auto-immune diseases and allergies) which we rather control than are able to cure,” Hensel says. “Owner compliance is certainly a very important factor which has a major impact on the success in managing a patient.

“However, some diseases can progress and the initial therapy can become less effective,” Hensel continues. “It is often a combination of chronic and compliance issues which result in relapses.”

Treatments/drugs

Authorities say many diseases can be cured successfully (e.g. parasites) and many drugs and products are available and effective, but not all drugs will

work on every patient and each case needs to be handled individually as Olivry advises.

“One big problem is over-the-counter products like flea preventives and shampoos,” Hensel says. “Often these don't show the same efficacy as those used by veterinarians, which veterinarians need to emphasize.”

Veterinarians will recommend diet changes for many allergy cases. Keeping the pet and owner happy with a new diet can be challenging.

Diet

“Diet plays an important role in the overall health of the entire body of an animal,” Hensel says. “Every animal should be on a high-quality and balanced diet to guarantee an intact immune system and health of the skin. For example essential fatty acids have been shown to increase skin health.”

In food-allergic cats and dogs, diet is key to managing the allergic reaction in the skin. For other allergic disorders, dietary supplements in addition to primary therapy or therapies can augment the management of the condition.

When a condition goes untreated, it can increase the incidence of risk for other pets and human members of the family.

Dangerous Conditions

Pruritus is probably the most serious condition for most parasitic and allergic diseases, Hensel says.

“If pruritus is not addressed, secondary infections of the skin and ears, especially in dogs, is a common problem,” Hensel says. “If the infections are not treated properly, the risk of developing multi-resistant bacteria is substantial. Methicillin-resistant Staph (MRS) infections are on the rise.”

Specialists say that resistant bacterial infections such as MRSA (aureus) or MRSE (epidermidis) are serious concerns for pets as well as humans.

While specialists say the number of resistant bacterial infections are on the rise, they add that dermatology offices are more likely to see these cases than any single practice.

“This is definitely becoming a public health concern,” Hensel says. “We see a lot of MRS infections in our patient pool. Animals can contract MRS infections by either contact with another animal carrying or infected with that specific organism or an animal can develop a MRS infection after inappropriate antibiotic therapy (e.g. several different antibiotics used; treatment duration too short or the dose of the antibiotic was too low).

“Hospitals, groomers, shelters and any other area with high animal traffic can be sources of infection. However, the primary organism for MRS in dogs and cats is Staph,” Hensel continues. “Pseudintermedius, while in people it is Staph. Aureus. At least so far, the risk for a pet owner to develop an infection with MRSP is very low, unless the client is heavily immune-suppressed. The same for the dogs, where we have not seen many MRSA infections so far.”

Antibiotic options are fewer when considering canine/animal patients in comparison to human, specialists say.

“These infections are usually more difficult to treat as there are fewer antibiotic options,” Koch says. “There are different types of Staphylococcus bacteria causing skin and ear infections in dogs and cats that can become antibiotic resistant.

“Whenever we diagnose MRSA, we try to investigate a possible source in the household, and also recommend isolating the animal if possible and practicing good hand hygiene at home,” Koch adds. “It is important to keep in mind that animals and humans can be asymptomatic carriers of this bacteria.

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