Spring ushers in the scratching season in dogs

Flea bites, allergies and humidity changes can all trigger painful hot spots


[From Tufts April 2010 Issue]

With the approach of warm weather, many owners resign themselves to their dogs’ intense itching and scratching. Even small skin abrasions can lead to a condition called pyotraumatic dermatitis, popularly known as hot spots. The often painful skin condition is a symptom of an underlying problem.

“There are a lot of different triggers for hot spots, but the most common are flea bites, allergies or local humidity changes in the fur,” says veterinary dermatologist and Your Dog advisory board member Lowell Ackerman, DVM. “Mites, cuts, insect bites, stings or saliva accumulation as a result of chewing can all trigger an inflammatory reaction and cause a hot spot to develop.”

Airborne irritants
In addition to fleas, among other allergens that could be to blame include food or airborne irritants such as dust, pollen and mold. Dogs also may develop hot spots after swimming in lakes and oceans because water changes the temperature and humidity of the skin. Poor grooming can also be a factor, allowing mats to form or undercoats to become trapped.

Although any dog—especially those with thick undercoats—can develop hot spots, certain breeds such as golden retrievers, Saint Bernards and German shepherd dogs are more susceptible.

Simply stated, a hot spot is an inflamed, raw spot that develops because of an irritation to the skin. In response, a dog will begin to lick or chew the area. Unless treated, the cycle of licking, chewing and scratching will continue, further aggravating the site.

Because hot spots can spread rapidly—from minutes to a few hours—prompt diagnosis and treatment are vital. “It’s important to aggressively manage hot spots in their early stages so they don’t progress deeper to the point where antibiotics are needed,” Dr. Ackerman says.

At first, a hot spot appears as a moist, itchy patch of skin with matted hair. Left untreated, infection sets in and the spot will begin oozing a yellow discharge. It will eventually dry, the damaged skin will form a crust, and the dog will lose hair over the infection. At this point, the spot is very sensitive to the touch because of the host of nerve endings on the surface of the skin.

They can heal quickly
While hot spots can appear serious and certainly make a dog miserable, they’re usually superficial and heal quickly, Dr. Ackerman says. “Hot spots can look life-threatening, but they normally involve only the top layers of skin unless infection develops and it moves deeper.”

Hot spots, which typically occur in summer, can appear anywhere on the body but are typically seen around the face, flank and tail. A hot spot over the hip may indicate flea infestation or anal sac infection; a hot spot on or near the ear could indicate allergy, an ear disorder or even a dental problem.

Veterinarians usually diagnose hot spots by their appearance. In some cases, they take skin scrapings—a sampling of skin cells—to evaluate under a microscope. They might also take bacterial cultures to identify the offending organism or organisms.

Dr. Ackerman, author of Guide to Skin and Haircoat Problems in Dogs (Alpine Publications), explains the steps veterinarians take in treatment. They will usually:

  1. Shave the fur around the inflamed skin until a boundary of normal-appearing skin is evident. This will allow the hot spot to dry and essentially creates a “firebreak” to stop the inflammatory reaction from spreading. “Depending on the pet, this might require some sedation since the condition can be painful to some animals,” Dr. Ackerman says.

  2. Clean the area with cool water and a gentle skin cleanser. Avoid the use of alcohol—it will sting if applied to the eroded surface.

  3. Apply topical sprays, such as hamamelis (witch hazel) and hydrocortisone.

  4. Possibly prescribe a short course of oral corticosteroid (Temaril-P, prednisolone, methylprednisolone or triamcinolone) to quickly reduce itchiness, pain and swelling. If caught early enough, antibiotics usually aren’t necessary.

As a general rule, ointments should be avoided as a means of treating hot spots, Dr. Ackerman says. “Ointments can actually seal the surface and force infection deeper. If infection develops, then antibiotics will be an additional requirement.”

After treatment, owners should exercise special care to encourage healing. “Once treatment is administered, whether oral or topical, it’s important to make sure a dog doesn’t further traumatize the area,” Dr. Ackerman says. “That’s why you often see dogs wearing Elizabethan collars. If the inflammation and any infection have been quickly controlled, the condition typically resolves in 7 to 10 days. If not, it might take up to four weeks to achieve resolution, so quick action is always worthwhile.”

Some dogs may develop one or two hot spots in their lives while others suffer frequent recurrences. Regular bathing and grooming with appropriate products may help lessen or prevent them, depending on the cause. A flea control product that your veterinarian recommends can also help.

Flea control is a must
While some owners may be concerned about using a chemical product on their dog, dermatologist Jean Greek, DVM, in Santa Barbara, Calif., points out that failing to use a flea preventive can actually be harmful to your dog.

“The fact is that flea control products are much safer and more effective than in the past. Ironically, it is often those dogs whose owners don’t use flea control products that end up being subjected to several steroid injections to mitigate the symptoms of hot spots,” she says.

As does Dr. Ackerman, Dr. Greek emphasizes the importance of finding the underlying cause of hot spots to prevent future infections. “Continually treating the symptom without finding the cause is counterproductive,” she says, explaining that some owners repeatedly take their dog to her clinic for the treatment of hot spots. “They are getting steroid injections over and over again. There is nothing that steroids cure—they just help to ease the symptoms. Finding the cause of a hot spot is key to solving the problem.”

The bottom-line advice from the dermatologists: Consult your veterinarian at the first sign of a hot spot, so you can work together to relieve your dog’s suffering. “Every animal is different and treatment solutions need to be tailored to the individual needs of the pet and the owner,” Dr. Ackerman says. The good news is that while hot spots may look scary, with appropriate veterinary care they heal completely in a matter of weeks—often without a scar. It pays to be vigilant and seek veterinary attention promptly.


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