Any dog can develop hot spots, but they are more common in dogs with:
- Thick coats
- Dirty and/or moist skin
- Fleas, allergies or an under-performing immune system
Dogs with a dense undercoat (German Shepherd, Bernese, Labrador, etc.) or matted hair are generally the most likely to develop a hot spot. This dense hair creates a humid and hot environment favorable for bacterial overgrowth. That's also why hot spots are more frequent in summer than in winter.
The primary cause is a skin irritation, which can have numerous causes! A vicious cycle of itching and scratching will start. This trauma to the skin barrier's ecosystem can lead to an overgrowth of bacteria on the skin (surface pyoderma), and an infection will then progress.
The affected skin patch often appears suddenly as a moist, oozing, reddened area that is painful and itchy to the dog. You may notice hair loss and a bad odor.
A hot spot is always a local lesion whose size may vary. It usually has a circular shape. A hot spot can appear anywhere on the body, but they are often present behind the ears, on the cheek or on the hips.
The irritation will cause the dog to scratch, lick and chew at the lesion, worsening the condition. It is not uncommon for the lesion to widen quickly (within a few hours).