Pyotraumatic dermatitis, also known as a hot spot or acute moist dermatitis, is a common infection of the skin surface of dogs, particularly those with thick or long coats. [1] It occurs following self-inflicted trauma of the skin. [1] Pyotraumatic dermatitis rarely affects cats. [1]
Signs
The dog persistently licks, chews, scratches or rubs at a focal area of skin, [2] which quickly causes hair loss. [1] The skin becomes red, moist and weeps. [1] The affected area is obviously defined and separate from the surrounding healthy skin and coat. [1] Usually only one area of the skin is affected. [1] The size of the affected area is variable. [3] If the area is difficult for the dog to scratch, or if the disease is caught early, hair may still be present. [3] Areas commonly affected include the rump above the tail, the head and neck near the ears, and the top and sides of the lumbar area. [3]
Cause
Pyotraumatic dermatitis is caused by self-inflicted trauma to the skin, which is incited by pain or irritation, such as infestation with fleas or lice, [4] irritation from clippers, [3] allergic skin diseases, [4] diseases of the anal sacs, [4] inflammation of the ear canal, [4] foreign bodies or irritants within the coat, [4] or pain in muscles or joints. [4] Skin maceration from repeated wetting of the coat or moisture in the fur can also be an inciting cause. [3] Flea infestations are the most common inciting factor. [1]
The inciting factor causes the dog to traumatize a small area of skin. [2] The affected skin weeps (that is, it exudes serum), [3] and this moist surface layer of skin can become colonized by bacteria, although the skin itself is not infected. [4] The affected area is usually painful, as nerve endings are exposed when the surface of the skin is eroded. [5] Hair which remains in the affected area holds in the moisture and further irritates the skin surface. [6] Continued itching by the dog can cause the affected area to enlarge rapidly in only a few hours. [4]
Pyotraumatic dermatitis is more common when the dog's environment is hot and humid. [3] Dogs with thick undercoats or long fur are most commonly affected, [1] but pyotraumatic dermatitis can occur in any dog. [4] Commonly affected breeds include the Airedale Terrier, Akita, American Pit Bull Terrier, Basset Hound, Golden Retriever, Great Pyrenees, Labrador Retriever, Leonberger, Pembroke Welsh Corgi, Peruvian Inca Orchid ( Peruvian Hairless Dog), Shiba Inu, and Xoloitzcuintle (Mexican hairless dog) [7] as well as the German Shepherd and St. Bernard. [4]
Treatment
There are several aspects to treatment: breaking the "itch-scratch" cycle by clipping the fur and cleaning the skin; [5] addressing the underlying painful or itchy condition which initially caused the animal to begin scratching; [2] and relieving the dog's discomfort, for example with steroid medications. [3]
The hair in and around the affected area is clipped before the skin is cleaned with an antiseptic, rinsed, and dried. [3] The dog may require sedation before the fur is clipped, as skin affected by pyotraumatic dermatitis can be painful. [3]
With treatment, pyotraumatic dermatitis resolves in 3–7 days, but can recur if the inciting factor is not addressed. [3]
References
- ^ a b c d e f g h i Hnilica, Keith A.; Patterson, Adam P. (2016). "Chapter 3. Bacterial skin diseases. Pyotraumatic dermatitis". Small Animal Dermatology: A Color Atlas and Therapeutic Guide (4th ed.). St. Louis, Missouri: Elsevier. pp. 49–50. ISBN 978-0-323-37651-8.
- ^ a b c Lewis, Diane T. (2016). "Chapter 18 Dermatologic disorders. Pyotraumatic dermatitis". In Schaer, Michael; Gaschen, Frederic P. (eds.). Clinical Medicine of the Dog and Cat (3rd ed.). CRC Press. p. 779. ISBN 9781482226072.
- ^ a b c d e f g h i j k Tim, Nuttall; Harvey, Richard G.; McKeever, Patrick J. (2009). "Chapter 1: Pruritic dermatoses. Pyotraumatic dermatitis". Skin Diseases of the Dog and Cat a Colour Handbook (2nd ed.). London: CRC Press. p. 18. ISBN 978-1-84076-539-7.
- ^ a b c d e f g h i j Miller, William H. Jr.; Griffin, Craig E.; Campbell, Karen L. (2013). "Pyotraumatic dermatitis". Muller & Kirk's Small Animal Dermatology (7th ed.). St. Louis, Missouri: Elsevier. pp. 677–678. ISBN 9781416000280.
- ^ a b Moriello, Karen A. (2011). Small Animal Dermatology (6th, rev. ed.). London: CRC Press. p. 90. ISBN 9781840766356.
- ^ Susan M. Ewing (4 May 2011). Poodles For Dummies. ISBN 9781118068120. Retrieved December 29, 2012.
- ^ Dodds, W. Jean (2011). "Guide to Congenital and heritable Disorders in Dogs: Includes Genetic Predispositions to Diseases" (PDF). Retrieved March 6, 2020.