Pyotraumatic Dermatitis - "Hot Spots"

Pet Tales
by Barry B. Burtis D.V.M.

"They're back! We just got home from the cottage yesterday.  I noticed one starting to bother Jasper last night but this morning it's a lot bigger and now there's another one beginning on the top of his head as well. Can I have an appointment to get him there for a visit quickly?"

The animal hospital receptionist knew Jasper well. An alert, friendly, 4 year old male blond Golden Retriever with a thick, soft, haircoat and long full hair growing from his legs and the underside of his body, he was a textbook picture of how a member of his breed should appear. She also knew his owner as someone who would not panic and demand immediate attention unless he really believed such urgency was necessary. She promptly found a spot in the morning work schedule to see Jasper. She knew that she had made the correct decision to do so, when she politely inquired as to exactly what was back again.  She was also immediately sympathetic and understanding when the client answered, in a tone, laced with anxiety and concern, "Hot spots, he's got hot spots again, just like last year!".

Hot spots is one of the common names given to a form of skin disease that is quite a frequent problem for certain breeds of dogs, especially in the warm weather months. It is also sometimes called summer itch or moist eczema. More proper terminology for the disease is pyotraumatic dermatitis, superficial pyoderma or acute moist dermatitis. The problem occurs most often in thick-coated, long-haired dogs. It is rare in cats.

Pyotraumatic dermatitis is more common in hot, humid weather when there is lack of ventilation in the haircoat and one of several predisposing factors is present. The skin lesion begins when the animal licks, chews, scratches or rubs at a particular area on its body in response to something that makes the area either itchy or painful. The constant attention to this area of skin traumatizes the skin and breaks the protective barrier the skin normally provides against bacterial invasion. An acute and rapidly developing surface bacterial skin infection results secondary to the self-inflicted trauma.

When Jasper arrived at the animal hospital it did not take long for the veterinarian to find the location of the skin lesion. The whole right side of Jasper's face was affected. A roughly circular lesion began below his ear and extended down to his jaw with the forward margins a few centimeters below his eye at the top and the corner of his lips below. A much smaller 2 centimeter diameter lesion was present on the top of his head. The affected skin surface was red, moist, erosive and ulcerated. The hair centrally in the lesion was gone but the margins of surrounding, apparently healthy tissue seemed quite clearly defined. On entering the exam room, poor Jasper had no time for his usual tail-wagging hello before he had to sit and vigorously scratch and scratch the area with his right rear paw. No question, he was hurting.

The diagnosis of the problem, as it was with Jasper, is usually quite straightforward. It will then be important, if possible, to identify and treat the underlying cause. Are there fleas or other parasites present that may have initiated an itchiness? Does the dog have an ear infection causing discomfort and rubbing? Are seasonal allergies responsible for a distressing itch? Is poor grooming of the haircoat involved? Is the affected area in a place where arthritis or another cause of pain could have caused the dog's attention? Could a hormone disorder have lowered the dog's resistance to bacterial infection?

Regardless of the answer to these questions, immediate attention must be given to patients suffering with the condition affecting Jasper. It is critically important to get the patient relief from the itchy, extremely uncomfortable and distressful feelings being experienced. Only when this is accomplished will Jasper and others like him be able to feel better, relax and have proper healing occur. Unchecked, more and more skin surface will become infected.                                                

The affected skin area is clipped with surgical number clipper blades and the area thoroughly cleaned with anti-bacterial soaps or cleansers. Often sedation will be necessary to do this in order to spare the patient discomfort and to allow a proper cleansing. Topical drying or astringent agents or steroid creams can then be applied. In most cases, especially if papules or pustules surround the central lesion, antibiotics will be necessary. Usually antibiotics, given by mouth, for 2-4 weeks are begun.

It is also very important to stop any further trauma being done to the area by the patient. This may require the use of Elizabethan or no-bite collars or bandaging of the foot being used for scratching, in addition to the use of medications previously mentioned. Owners should learn how to recognize early signs of the disorder and, if noticed, home care measures to be quickly begun, until they can get veterinary attention for their pet.

Readers will be pleased to know Jasper, as do most patients with this form of skin disease, made a complete and full recovery. The skin healed quickly and his hair grew back normally over the entire affected area.