Hot Spots
A hot spot, also known as acute moist dermatitis, occurs when an area of the skin becomes inflamed and "nasty-looking" in a very short period of time. Usually this is due to a superficial infection on the skin when the normal bacterial populations grow to abnormal levels and become irritating. It starts out as a tiny irritation on your dog's skin (that you probably didn't even notice). However, your dog did notice, and began to incessantly scratch, lick and chew the area until it developed into this terrible lesion. Sometimes this can occur in a few hours, so you will come home and notice this lesion that definitely was not there when you left!
Dogs with long hair and a "double-coat" seem to be predisposed to this condition. This includes such breeds as Golden Retrievers, Old English sheepdogs, Cocker Spaniels, and collies, although other breeds can be affected as well. It is thought that the level of humidity that is allowed to build up under the coat provides a good environment for bacteria to grow and cause the initial itching. If you have a dog with a long, easily matted coat, frequent brushing and bathing can help prevent the development of hot spots. Some people chose to give their dog a "shorter haircut" during the summer, to help decrease the amount of heat and humidity building up on the skin. Be sure to prevent mats and tangles from occurring in your dog's fur, and brush these mats and tangles out before bathing.
Treatment for hot spots includes clipping the hair in the area, cleaning the area thoroughly with an astringent or antiseptic, and daily treatments with cortisone cream or antibiotics for a few days to weeks afterward. Sometimes these can be hard to cure because the dog will not stop licking or chewing. In this case, your veterinarian may recommend a short course of corticosteroids to reduce the itchiness and inflammation associated with the spot. Sometimes hot spots are caused by allergies or related to a behavioral problem, such as boredom. In these cases, the underlying cause must also be treated to prevent reoccurrence. Unfortunately, dogs who get one hot spot seem to be prone to getting more.