Hot Spot on the skin = Superficial Pyoderma
This is Rusty, an 8 year old male staffy cross. He has just come back from a great week camping. He’s been playing with other dogs and going in and out off the lake. It was great fun but in the warm humid weather any scratch or irritation can turn into a skin infection.
Rusty has a superficial pyoderma (an infection of the top layer of skin), just below his left ear. It started as a little scratch but doubled in size today and he is feeling a little subdued. The red, hairless area is just the beginning. The skin infection is at least 3 times as big and there are little irritated areas down his neck that we call satellite lesions. With a couple of days of scratching this could easily change from 3 cm to 15cm of skin infection. 
Sometimes these will happen from itchy ears. Rusty has his ears smeared and they are very clear. There is just some debris on the slide, no organisms.
The skin infection can either be bacterial or be caused by yeast. An impression of the discharge on the wound shows lots of blobby neutrophils and some bacteria but no evidence of yeast.
With Rusty’s short fur we are not going to clip today but are going to wash in antibacterial shampoo. He is going to have a long antibiotic course and some medication to try to stop the itching. 
Even with this treatment the area of hair loss will most likely grow over the next few days. Then a few days later, it should dry out and start to heal. If the infections gets worse, he may need the dreaded elizabethan collar on his head to stop him itching and traumatizing the skin.
