Hairless areas on your dog that seem sensitive, and perhaps ooze a clear fluid or pus may be dog hot spots. Inflamed skin has allowed an infection to take hold, and the resulting area becomes extremely sensitive, perhaps painful or itchy. Properly called pyotraumatic dermatitis by veterinarians, these bacterial infections of the skin have several causes, including allergies, improper or insufficient grooming, and behavioral issues.
Irritation of the skin is necessary before an infection can take hold in a dog with a normal immune system. This irritation can result from allergies to parasites, food, or environment, matting or fur that creates a buildup of moisture and debris, or excessive licking or scratching caused by allergies, boredom, anxiety, or other behavioral issues.
Treatment requires supervision by a veterinarian, in case there is more to the issue than there appears to be. Probably, the suggested treatment will be clipping fur around the inflamed area short to allow access, and then washing on a regular basis with a gentle cleanser or antiseptic. If the irritation was caused by licking or scratching, the use of an e-collar might be recommended until the area heals.
The skin infection can often be treated relatively easily, but there is usually a larger problem behind it. Until this larger problem is resolved, the skin infections will only continue. Figuring out what is making the dog susceptible to these infections is the only way to stop them for good.
For dogs that have developed these issues because of improper grooming, better and more frequent grooming is indicated. Regular grooming sessions (twice a week or more) are necessary for the hygiene and health of dogs with long coats. Mats need to be removed at each grooming session, or they can result in excess moisture buildup against the skin. Clipping these mats out is sometimes necessary if they refuse to be detangled. Some owners are unable to provide their dogs with the necessary grooming needed for their health-- these owners can and should take their dog to a groomer regularly.
Allergic dogs can be allergic to almost anything they encounter regularly. Cleaning your dog's environment of as many of these possible allergens as is realistic is generally the first treatment. This requires treating for fleas, if any are present, treating the dog with a flea-preventative to avoid those that might be outdoors, switching to a lower-allergen food, and vacuuming to remove dust and pollen. Some dogs require an antihistamine, as well.
Behavioral issues such as licking can be the most difficult to treat. Usually, affected dogs are either bored or anxious. Treating these problems can help resolve the licking. Bored dogs will benefit from more exercise and training and toys to tire out the body and mind, and anxious dogs will benefit from similar help, as well as other exercises suggested by a trainer or behaviorist. Sometimes, anti-anxiety medications are called for.
Dog hot spots are an indication that something else is wrong with your pet. Aside from treatment for the issue itself, get some suggestions from your veterinarian as to how to resolve the larger issue. With appropriate care, most dogs can recover from the underlying problem and the skin issues will resolve themselves.