Hot spots, or acute moist dermatitis, are red, hot, irritated lesions that appear on the skin of your cat or dog. These hot spots can be painful and irritating, and are often made worse by the dog or cat licking and scratching at them. Hot spots are generally caused by allergic reactions to things like tick or flea bites, skin infections, poor grooming, and underlying skin or ear infections. If you suspect your dog or cat has a hot spot, it is best to bring them to your veterinarian as soon as possible, because they are known to get bigger fairly quickly. Hot spots are generally treated by shaving the area, cleansing it, and administering antibiotics. Your pet may also need medication for any parasites and an Elizabethan Collar to prevent them from picking at the affected area.