Hot Spots in Dogs

What is a hot spot?

Canine hot spots, also known as pyotraumatic dermatitis or acute moist dermatitis, are red, inflamed skin lesions that appear quickly, ooze, and may contain pus.

Hot spots can be found anywhere on a dog’s body, but the most common sites are the head, legs, and hips. These painful, itchy, smelly sores may be obvious or may be hidden under matted fur.

What causes hot spots?

Hot spots are usually caused by self-trauma when a dog scratches an itchy spot so vigorously that it creates an open wound. Many things can cause the initial itch in dogs, including:

• Allergies, including food allergies or inhalant allergies that cause itching.
• Reactions to insect bites from fleas, mites (Sarcoptes, Cheyletiella), or other small insects (e.g., caterpillars, bees, wasps, lice, gnats, or mosquitoes).
• Ear infections. Bacteria or yeast in the ear canal can be so irritating that the dog scratches at the ear, creating hot spots on the ear flap, behind the ear, or on the neck.
• Pyoderma. Primary skin infections caused by bacteria or yeast may incite the dog to scratch an area so much that a secondary hot spot forms.
• Poor grooming. Dogs with poorly-kept hair coats bite at tangles, creating open wounds. Matted fur prevents air from reaching the skin and retains water after a dog swims or gets caught in the rain, which ensures that the skin stays wet, creating a perfect environment for a hot spot.
• Boredom. Instead of biting their fingernails, bored dogs lick areas that are easily accessible. When they lie down, their feet and forearms are right under their faces, so hot spots often occur there.
• Orthopedic problems. Dogs with arthritis or back problems tend to lie down a lot. Lying on one side creates abrasions over pressure points, like hips or ankles, where bony protrusions have little muscular padding, especially in elderly dogs with decreasing muscle mass. When the dog licks the abrasion, a hot spot erupts. Dogs also lick or chew at degenerating joints much like people rub a sore knee to relieve the pain, creating hot spots in the process.
• Anal gland inflammation. Infected or impacted anal glands are painful and annoying. Dogs lick the area around the rectum and can cause hot spots under or on top of the tail.

When a dog licks the sore spot, it irritates superficial nerve endings in the skin, which stimulates more itching, followed by more licking, biting, and scratching. This lick-itch-lick cycle is the basis for the self-trauma that causes hot spots. Hot spots can dramatically increase in size in a very short period. Pet owners may go to work after noticing a pinpoint area of redness and come home to find a raw lesion the size of a pancake.

How are hot spots treated?

The goal in treating a hot spot is to stop the trauma and prevent the development of a deep skin infection. The first step in treatment is to stop the self-mutilation. Some options to prevent your dog from hurting themselves include:

• Using an Elizabethan collar (also known as an E-collar or cone) that stops the dog from chewing at the hot spot.
• Covering the hot spot with a sock or bandage to act as a barrier.
• Giving your dog topical or oral steroids and antihistamines to reduce the itching. Consult your veterinarian before using any medications intended for humans, as they are often toxic to dogs.

It often takes a combination of all options to stop the trauma. In the meantime, the underlying cause of the hot spot must be addressed. Treatment depends on the cause:

• Impacted anal glands: The anal glands will need to be expressed.
• Flea allergy: Your dog will need monthly flea control to eliminate fleas and control their life cycle (e.g., Frontline® Plus, Advantage®, Advantix®, Revolution®, Nexgard®, Simparica®, or Bravecto®).
• Arthritis: Your veterinarian may prescribe non-steroidal anti-inflammatory drugs (NSAIDs), such as meloxicam (Metacam®), carprofen (Rimadyl®, Vetprofen®), or deracoxib (Deramaxx®), or other pain medications such as gabapentin (Neurontin®).
• Inhalant or food allergies: Your veterinarian can help you begin allergen avoidance or desensitization therapy and may recommend a hypoallergenic diet.
• Ear infections: The underlying yeast or bacterial infection will be treated.
• Boredom or behavioral problems: Training and behavior modification, increased exercise and environmental enrichment, and sometimes medications such as fluoxetine (Reconcile®), clomipramine (Clomicalm®), or amitriptyline (Elavil®) may be recommended.
• Poor grooming: Seek a professional groomer who knows how to safely use clippers.

Clipping the hair away from the hot spot and the surrounding area is crucial to successful treatment. The hot spot will heal more quickly if the hair is removed so that the lesion can dry properly. Grooming may be painful, so your dog may need to be sedated.

After clipping, the lesion should be disinfected with a chlorhexidine solution that kills bacteria. Topical antibiotics, desiccating (drying) sprays, and soothing reagents will be more effective when applied to a clipped, clean skin surface. Oral antibiotics and steroids/antihistamines may also be helpful for serious hot spots. Warning: Do not use scissors to trim the hair away from the hot spot, as it is easy to accidentally cut your dog’s skin, resulting in an even greater problem that may require sutures.

How can hot spots be prevented?

Continued monitoring and treatment of the underlying cause should prevent future hot spots. Some dogs also benefit from seasonal grooming, as well as regular brushing and bathing.