Also known as acute moist dermatitis, hot spots are usually a disease of dogs with long hair or those with dense undercoats. It is often caused by a local allergic reaction to a specific antigen. Insect bites, especially from fleas, are often found to be the cause.
Other causes include atopy (inhalant allergies) and food allergies; mite infestations with Sarcoptes scabei or Cheyletiella; ear infections; poor grooming, burs or plant awns; hip dysplasia or other types of arthritis and degenerative joint disease; and anal gland disease.
Hot spots are circular lesions, usually found on the head, over the hip and along the side of the chest. They will be moist, raw, inflamed and hairless, and can be quite painful. Animals usually lick, bite or scratch the area, and thus irritate the inflamed skin even more. In fact, hot spots are sometimes called ‘pyotraumatic dermatitis’ because the self-trauma is a major factor in the development of hot spots.
Hot Spots can change dramatically in size in a very brief period of time. What was the size of a quarter may easily be eight inches in diameter in six hours.
The lesions are rare in the colder temperatures of winter. They occur in equal frequency in both inside and outside dogs. Many dogs develop several of these lesions over the course of their lives. However, this is not a long-term disease. A lesion will suddenly appear, be treated and be gone in less than a week Another lesion will suddenly appear later the same summer, the next year or never be seen again on that dog.
Treatment must be directed at stopping the growth of the hot spot and eliminating the cause. In many dogs the initial cause is fleas, but lesions below the ear often indicate an ear infection, those near the hip may be the result of an anal gland infection, and so on. Whatever the cause, if it can be detected, it must be treated while the hot spot is being treated.
The first step in treating hot spots is clipping the hair over and surrounding the lesion. This allows air to get into the inflamed tissue and makes it easier to treat. The surface of the lesion is then cleaned with a non-irritating solution such as dilute Nolvasan solution. To help the lesion heal desiccating powders such as Burows solution (Domeboro powder and water) are often then applied. If the dog is very sensitive this may need to be done under sedation. In more severe cases the animal may be placed on oral antibiotics and given painkillers and anti-inflammatories such as buffered aspirin or steroids. (Do NOT give your cat aspirin unless prescribed by your veterinarian.)
We also need to prevent the dog from traumatizing the area even more. Elizabethan collars (those plastic ’satellite dishes’) may be used if the lesion is on the top of the head, for instance. Nails can be clipped and socks can be put on the hind feet to reduce trauma from possible scratching.
Many dogs that have repeated problems with hot spots can have the incidence greatly reduced by keeping their hair clipped short during summer, giving them frequent medicated baths and following a strict flea control program. Depending on the location of the hot spot, cleaning the ears regularly and expressing the anal glands as needed may also be beneficial.