Common skin conditions in pets

Now that we have passed the April showers and received the May flowers, summer is officially beginning. Because of this, it is important to warn your clients of the dangers that lurk within the summer months such as fleas and ticks or fireworks and other celebrations that can cause anxiety in pets. However, there are dermatology cases that also need to be talked about and looked out for at the veterinary clinic.

Feline miliary dermatitis, pyotraumatic dermatitis, and flystrike are just a few dermatology cases that appear more in these hotter months. To help, here is a breakdown of these diseases, treatments, and how to talk to clients to help them keep their pets safe.

Dogs

A common summertime dermatology case is pyotraumatic dermatitis, or acute moist dermatitis (also known as hot spots). Hot spots are typically red and inflamed skin lesions that present themselves quickly and that ooze and may contain pus. Hot spots can be found anywhere on the dog’s body; they are typically found on the head, hips, and legs. These spots become painful and itchy and have an odor that can either stick out to pet parents or may be hidden underneath fur.¹

Hot spots are typically caused by self- trauma after a dog has scratched itself so harshly that it created an open wound. Allergies, ear infections, insect bites (such as fleas), pyoderma, and even boredom are among the most common causes of hot spots. VCA Animal Hospitals also warns that these spots can grow in a very short amount of time. In some cases, a pet owner had noticed a pinpoint area of redness on their pet before going to work, then returned home hours later to see a raw lesion the size of a pancake.

First and foremost, veterinary teams and the client must stop the pet from continuing to attack the spot. Then, successful treatment often includes combinations of using Elizabethan collars, covering hot spots with a sock or bandage, and administering topical or oral steroids and antihistamines to help reduce itching.

“The best way to prevent is to make sure your pet’s allergies are well controlled as they go into allergy season, and they are on good, consistent flea control to prevent flares from ectoparasites like fleas or even potentially scabies. Dogs with long, heavy coats should always be dried thoroughly to prevent moisture from sitting on the skin which can lead to irritation and in some cases pyotraumatic lesions can occur as a result,” said Joya Griffin, DVM, DACVD, host of Nat Geo’s Pop Goes the Vet With Dr. Joya.

Rabbits

Although rabbits are commonly kept in their cages inside the house, they are still at risk of summer dermatology diseases. In the summer months, veterinary teams should be cautioning rabbit owners about myiasis (also known as flystrike). Flystrike occurs when a fly gets into the cage and lays eggs on the rabbit, damaging the skin.² Those eggs then hatch into maggots, further damaging the skin and resulting in infected wounds.

Flies are going to be attracted to an area of the skin that is typically not clean or dry and can contain a disease that is affecting the skin, such as urine scalding, cutaneous abscesses, or bite wounds, or affecting grooming, such as Encephalitozoon cuniculi infection, osteoarthritis, or spondylosis.³ Once the fly decides where to land, it will lay its eggs on the skin, and depending on weather conditions, the eggs can hatch as quickly as within 12 hours to form the first stages of small and nonharmful maggots.

If the maggots are on the rabbit for 2 days, they will enter the second and third stages, which are larger and cause damage directly to the skin.³ Patients that have entered this stage will not appear to be in pain, but their coloring may be off and they can show signs of inappetence and lethargy.

Clients who find maggots on their pets must bring them to the veterinarian immediately, as these diseases can be fatal if not treated. Veterinary teams can instruct clients to remove maggots with tweezers if it does not delay their trip to the veterinarian. Advise clients to also avoid getting their rabbit wet, as the team may need to shave the fur.²

Flystrike is preventable by first treating any under-lying condition that may have caused the initial skin issue, then checking rabbits twice a day. Veterinary teams can also instruct clients to use fly screens or fly strips. Veterinary professionals can also prescribe topical treatments such as cyromazine.³

Cats

Feline miliary dermatitis is commonly used to describe a feline skin condition that is the result of an allergic reaction. Cats with feline miliary dermatitis will present with an extremely itchy rash that they may be licking, biting, and scratching at. In some cases, even just touching the affected area will cause the patient to start scratching, licking, or twitching.⁴ This rash will progress into small, scabbed lesions and can be caused by self-trauma or allergic reaction. The rash can become infected in severe feline miliary dermatitis cases and will present with pustules or pimplelike lesions.

Although multiple underlying conditions can cause feline miliary dermatitis, the most common cause is an allergic reaction to flea bites, but it can also be caused by environmental allergens or allergens in the pet’s diet. Patients with this disease will typically present with infected areas on the lower spine, face, ears, belly, beck, flank, and around the base of the cat’s tail, with the patient’s coat thinning in the affected areas.

Once identified, topical treatments can be used if feline miliary dermatitis is caused by mites or lice. If it is caused by food, a hypoallergenic food trial could be done to rule out or identify a food allergy. To help ease any pain or discomfort, veterinarians can prescribe antihistamines; essential fatty acids; topical treatment, such as calming or antiseptic sprays or mousses;
and cyclosporine.⁴

“Ruling out the causes for miliary dermatitis is important so you can determine and tackle the exact cause. Treating with an ectoparasiticide is one of the first steps to rule fleas and demodex gatoi,” explained Griffin. “Then if not improved, starting a novel protein diet trial is important especially if no clear seasonality is present. If no improvement is seen after a 6-8 week diet trial, then further work up and treatment for environmental allergies can be initiated.”

Esteban Soto Martinez, DVM, PhD, DACVM (Bacteriology/Mycology and Immunology) holding a koi fish. (Photo courtesy of UC Davis School of Veterinary Medicine)

Koi fish

Koi fish may not be the most common animal seen at your practice, but being prepared with knowledge of diseases that affect them can help save their lives. A big risk to koi fish is koi herpesvirus (KHV), also known as Cyprinid herpesvirus 3, carp interstitial nephritis, or gill necrosis virus.⁵ KHV is a highly contagious viral pathogen, with the mortality rates being influenced by factors such as the virulence of the strain of the virus, the age of the fish, and the temperature of the water.

Koi fish with KHV will present with a variety of clinical signs, including difficulty breathing, gathering near oxygen-rich areas, piping, excessive mucous production from gills, swollen gills, gill necrosis/ discoloration, or erratic swimming. Once the first of any of these clinical signs presents themselves, mortality rates are at their highest between 48 and 72 hours.

There is currently no treatment for KHV. The University of California Davis School of Veterinary Medicine recommends making the temperature of the water below 60 °F and increasing the salinity to 0.05 to 3.00 parts per thousand to help with controlling secondary bacterial, fungal, osmoregulation, and parasitic infection.⁵ For any clients who suspect KHV, warn them to not add antibacterial, antifungal, or antiparasitic treatments to the water unless told to do so, as they have no direct benefits to fighting this disease and can cause damage to the fishes’ already compromised gills.

Because there is no treatment, preventive methods are needed to manage this disease. Any clients who are interested in purchasing fish should do so from reputable sources and can have an ELISA blood test done to look for previous exposures. The test can detect antibody reactivity long after the virus is gone. New fish to any existing koi pond should be quarantined separately for at least 6 weeks at virus-permissible temperatures and be monitored for abnormal appearances and behavior.⁵

References

1. Williams K, Llera R, Ward E. Hot spots in dogs. VCA Animal Hospitals. Accessed May 18, 2023. https://vcahospitals.com/know-your-pet/hot-spots-in-dogs
2. Varga M. Flystrike in rabbits. University of Liverpool. Reviewed December 2021. Accessed May 18, 2023. https://www.liverpool.ac.uk/savsnet/focus-on-disease/ flystrike-in-rabbits/
3. Flystrike in rabbits. Rabbit Welfare Association & Fund. Accessed May 18, 2023. https://rabbitwelfare.co.uk/flystrike-in-rabbits/
4. Weir M, Hunter T, Ward E. Miliary dermatitis in cats. VCA Animal Hospitals. Accessed May 19, 2023. https://vcahospitals.com/know-your-pet/ feline-miliary-dermatitis
5. Young A. Koi herpesvirus (KHV). University of California, Davis. June 15, 2020. Accessed May 19, 2023. https://healthtopics.vetmed.ucdavis.edu/health-topics/ koi-herpesvirus-khv