Allergies and resistant staph infections dominate dermatological concerns
Knowing when to culture and when to refer can quell owner anxiety
By Jessica Tremayne
Veterinary dermatologists say general practitioners following the “three strikes and you’re out,” policy tend to hold onto the client they referred when future veterinary care is needed. While the down economy may make an owner less willing to comply with treatment, holding onto a case without results for too long can make them leave the practice for good.
Just as in general practice, specialists are reporting a slight decline in business correlating with their local economic conditions and the clients’ perceived importance of the problem, but they are also saying clients discuss their disappointment when their pet’s condition persisted for months even with their general practitioner’s treatments.
“The general vet should refer cases that have been seen by multiple veterinarians without resolution,” says Terry Nagle, BVSc, MACVS, Diplo. ACVD, Northern California Vet Specialists, Sacramento, Calif. “The chance of making this client happy is very low considering the previous generalists likely treated the animal following the most likely diagnosis. The referring vet can be the hero that referred to a specialist that has the background to treat the animal’s tricky case.”
Specialists say allergic dermatitis is still the most common reason they see clients, but the animal’s secondary bacterial infection is often the final straw that prompts a visit.
Telemedicine is a newer option to general practitioners interested in specialty advice prior to referral. A veterinarian can consult with a veterinary dermatologist via the Internet with programs such as Veterinary Answers, VDIC, dermatology consultations with biopsy reports (VCA Antech), and online chat groups.
“Telemedicine can circumvent the need to refer, but they cannot be a substitute to a specialist’s visualization of the issue,” says Alexander Werner, VMD, Diplo. ACVD, Animal Dermatology Center, Studio City, Calif. “Veterinarians should see referring clients to specialists as an extension of his or her practice. Also, a specialist’s effectiveness can only be as good as the quality of the patient’s provided medical history and samples.”
New dermatological drugs include Convenia (cefovectin sodium) has shown to be effective especially for feline patients, according to Dr. Schick. Convenia is a semi-synthetic broad-spectrum antibacterial agent from the cephalosporin class of chemotherapeutic agents, administered subcutaneously.
“My only concern with Convenia is compliance,” says Anthea E. Schick, DVM, Diplo. ACVD, Arizona Veterinary Specialists, LLC, Gilbert, Arizona . “The owner thinks the animal looks better, and they don’t need a second injection, but what happens is the first shot eliminated some bacteria, but not all, so it comes back. To increase owner compliance, we have the client pay for both injections on the first visit, and then they are more willing to return.”
Currently, cyclosporine is commonly used off-label by veterinarians for feline patients, but the drug could acquire FDA approval for cats.
“Atopica has been FDA approved for canine patients for about seven years, but it would be beneficial to have an FDA approval for feline use as well,” says Ian Spiegel, VMD, MHS, Diplo. ACVD, Red Bank Veterinary Hospital, Tinton Falls, NJ. “In the near future, we’ll likely see more medications specifically targeting receptors on cells involved in allergic reactions, such as tyrosine kinase inhibitors (mast cells), for dermatologic use.”
On the rise
Methicillin-resistant staphylococcal aureus (MRSA) or Methicillin-resistant staphylococcal pseudintermedius (MRSP) infections are increasing according to laboratory results, but since this isn’t a reportable-condition in veterinary medicine, an exact percentage of the increase of incidents is unknown. Idexx Reference Laboratories however, tracks the cases its laboratories identify.
“I have seen more cases of staph resistant infections in the last year, than in the last five years combined,” Dr. Schick says. “This doesn’t have to cause great alarm because it’s only the aureus strain that is causing concern for humans. If an animal does show to be aureus positive, it’s still not the end of the road for the pet.”
Specialists say the best way to approach cases of MRSA is for owners to follow common sense rules: good hygiene, use rinses, shampoos and topical more although they aren’t as neat and easy as an oral pill or injection, they work.
“In our litigious society, there will eventually be a lawsuit against a veterinarian because a person falls ill with a resistant infection and an animal in the household has the same bacterium,” Dr. Werner says. “But practicing defensive medicine isn’t a solution to that concern. Euthanasia isn’t the answer to the condition, there are antibiotics that work on these strains, it’s just more of a challenge.”
Before any diagnosis can be made, a culture must be done, a step specialists say many generalists forego.
“Veterinarians should consider culturing skin lesions if a commonly effective antibiotic was chosen and the correct dose, frequency of administration and duration were appropriate,” Spiegel says. “This might not be happening as much as it should due to owners’ financial concerns, but cultures eliminate the guesswork and in some cases, promotion of further resistance.”
Another dermatological condition on the rise is demodicosis caused by demodex injai. This form of demodex is a newly recognized disorder that is found mostly in specific breeds of canine patients.
“This emerging condition presents with greasy hair on the dog’s back, minimal hair loss and some facial irritation,” Schick says. “This new mite has a longer body than other demodex mites and fewer seem to be present upon examination of a skin scraping.”
Shi h Tzu dogs and terriers seem to get demodex injai more than other breeds and sedation may be required to collect a skin scraping considering the face is often affected most.
“Not a lot is known about demodex injai just yet,” Schick says. “Terriers that have been treated with steroids for allergies are commonly affected, but it’s hard to say if the mite was in abundance before the drugs were given, or if we’re looking at immune suppression.”
Dermatology experts say general veterinarians tend to treat allergic patients with bacterial infections for too short of a time frame, often just two weeks. In order to ensure the antibiotic has been successful three-four week regimen is recommended.
“There is a great reluctance to treat animals with an antibiotic long enough,” Spiegel says. “It’s better to gain control of the bacterial infection the first time, than to use multiple short courses of antibiotics. Successful management of bacterial and yeast infections, allows the veterinarian to focus on determining and eventually managing the underlying cause or causes.”
Spiegel says the reluctance to treat for a 3-4 week span may be a concern of side effects or boosting drug resistance. Regardless of the rational, Spiegel isn’t alone in this thought, citing a difference in canine skin from human is why extended use is necessary.
“We need to do a better job of protecting allergic animals’ skin before it gets to the point of having secondary bacterial infections,” says Mitchell Song, DVM, Animal Dermatology Service, Phoenix, Arizona. “In the case where a patient has confirmed resistant bacteria, veterinarians are limited to the antibiotics they can use. Veterinarians largely agree to not use Vancomycin or linezolid (Zyvox) in patients because it is reserved as a human rescue drug. There are still some other antibiotic options.”
The dermatology sector is constantly evolving, looking for more effective treatments with faster results. Schick’s practice is currently involved in a clinical trial for a drug that would be used in atopic dermatitis cases.
“This currently confidential drug would be used in cases where other drugs were used, but failed,” Schick says. “We are just one of several clinics trying this drug out and it is in its final stages of testing. I think the next couple of years will reveal several new effective dermatological drugs.” <HOME>
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Allergies and resistant staph infections dominate dermatological concerns
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