What Causes Hot Spots on Dogs: 6 Common Causes to Watch Out For

Environmental factors play a significant role in the development of hot spots on dogs, particularly during warm, humid months when moisture can become trapped in the coat. Summer swimming, rain exposure, or even high humidity can create the perfect breeding ground for bacteria when moisture lingers in dense fur. Dogs with thicker coats are especially vulnerable as poor air circulation between skin and fur creates warm, damp conditions in which bacteria thrive. These seasonal influences explain why many veterinarians report increased hot spot cases during the spring and summer months.

Allergies represent one of the most common underlying causes of hot spots on dogs, triggering intense itching that leads to the scratch-lick cycle. When a dog experiences an allergic reaction, inflammatory chemicals are released throughout the body, causing skin irritation and the overwhelming urge to scratch. This self-trauma damages the skin barrier, allowing bacteria to penetrate and multiply rapidly. For many dogs, hot spots represent the visible manifestation of an allergic condition that requires comprehensive management beyond just treating the lesion itself.

Common Allergens That Cause Hot Spots on Dogs

• Environmental allergens such as pollen, mold, dust mites, and grass can trigger seasonal allergic reactions leading to skin irritation and subsequent hot spots, particularly affecting a dog’s paws, belly, and face.
• Food sensitivities to common ingredients like chicken, beef, dairy, or grains may cause systemic allergic responses that manifest as skin inflammation and itching, prompting the dog to create hot spots through excessive licking.
• Flea bite hypersensitivity represents an extreme allergic reaction to flea saliva that can cause intense itching and discomfort from just a single bite, making it a common hot spot trigger in sensitive dogs.
• Contact allergens including certain fabrics, cleaning products, lawn chemicals, or even plastic food bowls can cause localized skin reactions where contact occurs, potentially developing into hot spots.
• Insect bites from mosquitoes, ants, bees, or other insects can create localized irritation that dogs obsessively lick or scratch, leading to hot spot formation.

Ear infections frequently contribute to hot spot development, particularly those appearing on a dog’s neck, cheek, or behind the ears. The intense discomfort of an ear infection often drives dogs to scratch vigorously at their ears or rub their head against furniture and floors seeking relief. This repetitive trauma damages the skin and creates the perfect entry point for bacteria. Additionally, discharge from infected ears can contaminate surrounding skin and fur, introducing pathogens directly to vulnerable areas that develop into painful hot spots on dogs.

Types of Ear Infections Associated with Hot Spots on Dogs

• Otitis externa affects the outer ear canal and is often characterized by redness, swelling, and discharge, causing dogs to scratch around their ears and face, frequently leading to hot spots in these areas.
• Yeast infections within the ear produce a distinctive sweet or musty odor along with a dark, waxy discharge, creating intense itching that can cause dogs to develop hot spots from excessive scratching.
• Bacterial ear infections typically present with yellowish or greenish discharge and strong odor, causing significant pain that leads to trauma-induced hot spots on the face and neck region.
• Otitis media/interna (middle/inner ear infections) can cause neurological symptoms alongside pain, leading to different scratching patterns and potential hot spot development in less typical locations.

Bacterial infections represent both a cause and complication of hot spots on dogs, creating a challenging cycle of skin damage. While normal skin hosts millions of bacteria without issue, when the skin barrier becomes compromised through injury, allergen exposure, or excessive moisture, these bacteria can rapidly multiply and invade deeper tissues. Staphylococcus intermedius, the most common culprit, produces enzymes and toxins that further damage the skin and increase inflammation. The moist, warm environment of a developing hot spot creates ideal conditions for bacterial proliferation, explaining why these lesions can expand dramatically within just 24 hours without proper intervention.

Underlying medical conditions can significantly increase a dog’s susceptibility to developing hot spots by compromising the skin’s natural defenses or triggering self-trauma. Dogs with endocrine disorders often experience changes in skin integrity, oil production, and immune function that make them more vulnerable to bacterial overgrowth. Similarly, pain from orthopedic conditions may cause dogs to lick affected areas excessively, creating entry points for bacteria. Identifying and managing these underlying conditions is essential for preventing recurrent hot spots and improving the dog’s overall quality of life.

Medical Conditions That Cause Hot Spots on Dogs

• Hypothyroidism causes hormonal imbalances that alter skin barrier function and oil production, leading to dry, flaky skin that’s more susceptible to infection and inflammation when scratched.
• Cushing’s disease (hyperadrenocorticism) results in thin, fragile skin with increased susceptibility to trauma and infection, while also suppressing the immune system’s ability to fight bacterial colonization.
• Arthritis and joint pain often lead dogs to lick painful areas excessively, creating moist skin conditions ideal for hot spot development, particularly on legs and paws near affected joints.
• Anal gland problems cause dogs to scoot and chew at their rear end, frequently leading to hot spots around the base of the tail, hips, and lower back regions.
• Immune-mediated skin diseases like pemphigus or lupus compromise normal skin defenses, creating vulnerability to bacterial invasion and subsequent hot spot formation even with minimal trauma.
• Behavioral conditions including anxiety, stress, and compulsive disorders can manifest as excessive licking or chewing behaviors that damage the skin barrier and create entry points for infectious agents.

When diagnosing hot spots on dogs, veterinarians follow a systematic approach to identify both the immediate issue and any underlying causes. Proper diagnosis is crucial as hot spots on dogs can sometimes resemble other skin conditions like ringworm, fungal infections, or even certain types of tumors. Early and accurate identification ensures appropriate treatment and helps prevent the recurrence of these painful skin lesions.

• Visual examination of the affected area, where the veterinarian assesses the size, appearance, and characteristics of the hot spot, noting details like redness, moisture, hair loss, and the precise location on the body.
• Patient history review involves discussing when the hot spot first appeared, any previous occurrences, potential triggers, and changes in the dog’s environment or routine that might contribute to the condition.
• Skin cytology requires collecting a sample from the affected area using a slide, swab, or tape strip, and then examining it under a microscope to identify bacteria types, yeast, or inflammatory cells present in the lesion.
• Ruling out other conditions might include fungal cultures, skin scrapings for mites, or even biopsies in cases where hot spots on dogs appear unusual or don’t respond to standard treatment.
• Identifying underlying issues such as skin allergies, ear infections, parasites, or pain sources that might be triggering the dog’s scratching or licking behavior leading to hot spot formation.

Professional hot spot treatments typically follow a multi-step approach aimed at relieving discomfort, addressing infection, and preventing further self-trauma. Veterinarians customize treatment based on the severity, location, and underlying causes of the hot spot. Quick intervention is essential as these painful lesions can expand rapidly, causing increasing discomfort for affected dogs.

• Clipping and cleaning the area involves carefully removing hair around the hot spot to expose the affected skin, then gently cleansing with antiseptic solutions to remove debris, discharge, and bacteria.
• Topical medications such as medicated sprays, creams, or ointments containing antibiotics, anti-inflammatory agents, or antiseptics are applied directly to the hot spot to fight infection and reduce inflammation.
• Oral medications may include antibiotics to address bacterial infection, anti-inflammatory drugs to reduce swelling and discomfort, or antihistamines to help control itching, especially when hot spots on dogs are widespread or severe.
• Prevention of further self-trauma through the use of Elizabethan collars (e-collars), surgical suits, or bandages to stop the dog from licking, chewing, or scratching the affected area during the healing process.
• Treatment of underlying causes targets the root issues like allergies, parasites, or ear infections that may have triggered the hot spot development, which is essential for preventing recurrence.
• Follow-up care involves reassessing the hot spot after 5-7 days of treatment to ensure proper healing and make any necessary adjustments to the treatment plan based on the dog’s response.