Title: Pyotraumatic dermatitis

{{short description|Skin disease of dogs and cats}}
[[File:HotSpot dog.jpg|thumb|Hot spot on a [[Golden Retriever]]]]
'''Pyotraumatic dermatitis''', also known as a '''hot spot'''  or '''acute moist dermatitis''', is a common infection of the skin surface of [[dog|dogs]], particularly those with thick or long coats.&lt;ref name=&quot;Hnilica 2016&quot;/&gt; It occurs following self-inflicted trauma of the skin.&lt;ref name=&quot;Hnilica 2016&quot;&gt;{{cite book|last1=Hnilica|first1=Keith A.|last2=Patterson|first2=Adam P.|title=Small Animal Dermatology: A Color Atlas and Therapeutic Guide|date=2016|publisher=Elsevier|location=St. Louis, Missouri|isbn=978-0-323-37651-8|pages=49–50|edition=4th|chapter-url=https://books.google.com/books?id=xT_UDAAAQBAJ&amp;pg=PA49|chapter=Chapter 3. Bacterial skin diseases. Pyotraumatic dermatitis}}&lt;/ref&gt; Pyotraumatic dermatitis rarely affects [[cats]].&lt;ref name=&quot;Hnilica 2016&quot;/&gt;

==Signs==
The dog persistently licks, chews, scratches or rubs at a focal area of skin,&lt;ref name=&quot;Schaer 2016&quot;/&gt; which quickly causes hair loss.&lt;ref name=&quot;Hnilica 2016&quot; /&gt; The skin becomes red, moist and weeps.&lt;ref name=&quot;Hnilica 2016&quot; /&gt; The affected area is obviously defined and separate from the surrounding healthy skin and coat.&lt;ref name=&quot;Hnilica 2016&quot; /&gt; Usually only one area of the skin is affected.&lt;ref name=&quot;Hnilica 2016&quot; /&gt; The size of the affected area is variable.&lt;ref name=&quot;Nuttall 2009&quot; /&gt; If the area is difficult for the dog to scratch, or if the disease is caught early, hair may still be present.&lt;ref name=&quot;Nuttall 2009&quot; /&gt; 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.&lt;ref name=&quot;Nuttall 2009&quot; /&gt;

==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,&lt;ref name=&quot;Miller 2013&quot;/&gt; irritation from clippers,&lt;ref name=&quot;Nuttall 2009&quot; /&gt; allergic skin diseases,&lt;ref name=&quot;Miller 2013&quot;/&gt; diseases of the anal sacs,&lt;ref name=&quot;Miller 2013&quot;/&gt; inflammation of the ear canal,&lt;ref name=&quot;Miller 2013&quot;/&gt; foreign bodies or irritants within the coat,&lt;ref name=&quot;Miller 2013&quot;/&gt; or pain in muscles or joints.&lt;ref name=&quot;Miller 2013&quot;&gt;{{cite book|last1=Miller|first1=William H. Jr.|last2=Griffin|first2=Craig E.|last3=Campbell|first3=Karen L.|title=Muller &amp; Kirk's Small Animal Dermatology|date=2013|publisher=Elsevier|location=St. Louis, Missouri|isbn=9781416000280|pages=677–678|edition=7th|chapter=Pyotraumatic dermatitis}}&lt;/ref&gt; [[Skin maceration]] from repeated wetting of the coat or moisture in the fur can also be an inciting cause.&lt;ref name=&quot;Nuttall 2009&quot; /&gt; Flea infestations are the most common inciting factor.&lt;ref name=&quot;Hnilica 2016&quot; /&gt;

The inciting factor causes the dog to traumatize a small area of skin.&lt;ref name=&quot;Schaer 2016&quot;&gt;{{cite book|editor-last1=Schaer|editor-first1=Michael|editor-last2=Gaschen|editor-first2=Frederic P.|title=Clinical Medicine of the Dog and Cat|publisher=CRC Press|last=Lewis |first=Diane T.|isbn=9781482226072|page=779|edition=3rd|chapter-url=https://books.google.com/books?id=DBRjDAAAQBAJ&amp;pg=PA779|date=2016|chapter=Chapter 18 Dermatologic disorders. Pyotraumatic dermatitis}}&lt;/ref&gt; The affected skin weeps (that is, it [[exudate|exudes serum]]),&lt;ref name=&quot;Nuttall 2009&quot; /&gt; and this moist surface layer of skin can become colonized by bacteria, although the skin itself is not infected.&lt;ref name=&quot;Miller 2013&quot; /&gt; The affected area is usually painful, as nerve endings are exposed when the surface of the skin is eroded.&lt;ref name=&quot;Moriello 2011&quot;/&gt; Hair which remains in the affected area holds in the moisture and further irritates the skin surface.&lt;ref name=&quot;google3&quot;&gt;{{cite book|url=https://books.google.com/books?id=QEf_kvw53fgC&amp;pg=PA214|title=Poodles For Dummies |author=Susan M. Ewing |date=4 May 2011 |isbn=9781118068120 |access-date=December 29, 2012}}&lt;/ref&gt; Continued itching by the dog can cause the affected area to enlarge rapidly in only a few hours.&lt;ref name=&quot;Miller 2013&quot; /&gt;

Pyotraumatic dermatitis is more common when the dog's environment is hot and humid.&lt;ref name=&quot;Nuttall 2009&quot; /&gt; Dogs with thick undercoats or long fur are most commonly affected,&lt;ref name=&quot;Hnilica 2016&quot; /&gt; but pyotraumatic dermatitis can occur in any dog.&lt;ref name=&quot;Miller 2013&quot; /&gt; Commonly affected breeds include the [[Airedale Terrier]], [[Akita (dog)|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)&lt;ref name=&quot;Dodds, 1994(2011)&quot;&gt;{{cite web | last = Dodds | first = W. Jean | title = Guide to Congenital and heritable Disorders in Dogs: Includes Genetic Predispositions to Diseases | year = 2011 | url = https://www.hsvma.org/assets/pdfs/guide-to-congenital-and-heritable-disorders.pdf | access-date = March 6, 2020 }}&lt;/ref&gt; as well as the [[German Shepherd]] and [[St. Bernard (dog)|St. Bernard]].&lt;ref name=&quot;Miller 2013&quot; /&gt;

==Treatment==
There are several aspects to treatment: breaking the &quot;itch-scratch&quot; cycle by clipping the fur and cleaning the skin;&lt;ref name=&quot;Moriello 2011&quot;&gt;{{cite book|last1=Moriello|first1=Karen A.|title=Small Animal Dermatology|date=2011|publisher=CRC Press|location=London|isbn=9781840766356|page=90|edition=6th, rev.|url=https://books.google.com/books?id=WfIyoF2bfhoC&amp;pg=PA90}}&lt;/ref&gt;
addressing the underlying painful or itchy condition which initially caused the animal to begin scratching;&lt;ref name=&quot;Schaer 2016&quot; /&gt; and relieving the dog's discomfort, for example with steroid medications.&lt;ref name=&quot;Nuttall 2009&quot;&gt;{{cite book|last1=Tim|first1=Nuttall|last2=Harvey|first2=Richard G.|last3=McKeever|first3=Patrick J.|title=Skin Diseases of the Dog and Cat a Colour Handbook|date=2009|publisher=CRC Press|location=London|isbn=978-1-84076-539-7|page=18|edition=2nd|chapter-url=https://books.google.com/books?id=CvHazimbX5oC&amp;pg=PA18|chapter=Chapter 1: Pruritic dermatoses. Pyotraumatic dermatitis}}&lt;/ref&gt; 

The hair in and around the affected area is clipped before the skin is cleaned with an antiseptic, rinsed, and dried.&lt;ref name=&quot;Nuttall 2009&quot; /&gt; The dog may require sedation before the fur is clipped, as skin affected by pyotraumatic dermatitis can be painful.&lt;ref name=&quot;Nuttall 2009&quot; /&gt;

With treatment, pyotraumatic dermatitis resolves in 3–7 days, but can recur if the inciting factor is not addressed.&lt;ref name=&quot;Nuttall 2009&quot; /&gt;

==References==
{{reflist}}
* [https://banixx.com/hot-spots-dog-how-to-treat/ Dog Hot Spot Treatment]

[[Category:Dog diseases]]
[[Category:Cat diseases]]