If you’ve ever noticed a sudden red, irritated patch of skin on your dog that seems to grow larger by the hour, you may be dealing with a hot spot. 

Hot spots on dogs, also known as acute moist dermatitis or pyotraumatic dermatitis, are painful, fast-spreading skin infections. They can grow from a tiny red patch to an oozing sore in just hours, especially if your dog keeps licking or scratching. Left untreated, they can develop into deeper bacterial skin lesions and recurring issues.

Let’s talk more about it so we can protect our dogs from these painful sores.

What Causes Hot Spots on Dogs?

Hot spots don’t just pop up for no reason. There’s always a trigger, a cause, that should be looked into. But here’s the good news: most of these causes are easy to spot once you know what to look for.

Let’s break it down into medically relevant categories. Here are the common causes of hot spots on dogs:

Allergies

Allergies are a common enemy, and it’s not different with hot spots. These can include:

• Environmental allergies. Pollen, grass, mold, and dust can cause itching and irritation.

• Food allergies. Certain ingredients, like chicken, beef, or dairy, may trigger allergic reactions in some dogs.

• Flea allergies. Even one single flea bite can cause itching for dogs with flea allergy dermatitis.

Parasites

Fleas, ticks, and mites are a common source of itching for dogs. When these parasites bite or burrow into the skin, they can cause irritation that causes excessive scratching or licking. This behavior damages the skin and creates the perfect conditions for bacteria to take hold and form a hot spot.

Poor Grooming

When a dog’s coat is neglected, mats and tangles can form, trapping dirt, bacteria, and moisture close to the skin. This creates irritation and inflammation, increasing the likelihood of hot spots in your dog. Because of this, regular grooming is very important, especially for dogs with thick fur.

Additionally, dogs with thick or long fur are particularly vulnerable to hot spots caused by trapped moisture. After swimming, bathing, or even getting caught in the rain, moisture can linger under their coat if they aren’t dried thoroughly. 

This means that it’s important to dry your dog up after a swim or bath.

The damp environment encourages bacteria growth, which can quickly lead to a hot spot. Yes, even leaving your dog wet can be a problem. It’s all in the little things.

Skin Trauma

Matted fur, post-surgery licking, and even small wounds can create localized irritation. Add bacteria into the mix and the result can be a hot, oozing sore.

Behavioral Causes

Stress, anxiety, or boredom can cause repetitive licking or chewing. Dogs may focus on one area obsessively, leading to a moist, raw patch of skin, what vets sometimes refer to as moist eczema.

Infections

Sometimes, hot spots are secondary to another issue, such as a skin or ear infection. For example, a dog with an ear infection might scratch or rub the area excessively, creating the conditions for a hot spot to form. Hot spots can start small and, if not addressed, can worsen and lead to more infections.

Infections in other parts of the body can also cause localized irritation that leads to these lesions.

Stress or Boredom

Stress and boredom can lead to repetitive behaviors in dogs, such as licking, chewing, or biting their skin. Over time, this can damage the skin’s surface and result in a hot spot. Stress may be caused by changes in routine, new environments, or separation anxiety, while boredom often occurs when dogs don’t get enough mental stimulation or exercise.

So be sure to keep your dogs happy and healthy.

Orthopedic Pain or Underlying Disease

Dogs with joint pain (such as arthritis) may lick the affected area excessively, especially on elbows or hips. Hormonal issues like hypothyroidism can also predispose dogs to skin infections.

Insect Bites

Stings or bites from mosquitoes or ants may cause a localized irritation that develops into a hot spot after self-trauma.

What Do Hot Spots Look Like on Dogs?

Hot spots can appear suddenly and worsen quickly, making it important to recognize the signs early. These inflamed, irritated areas of skin are not only uncomfortable but can also cause some serious infections in your dog.

One of the first signs that your dog might have a hot spot is their behavior. Dogs with hot spots will be visibly disturbed and uncomfortable. They tend to lick it nonstop in an attempt to relieve the irritation. Unfortunately, this only makes the problem worse. 

Constant licking, chewing, or scratching creates more problems and worsens the condition of your dog’s skin.

Hot spots are often easy to spot because of their distinct appearance. They appear as areas of red, irritated skin that stand out from the surrounding healthy skin. The affected area may feel warm or even hot to the touch. 

As the hot spot progresses, you might see swelling or thickened skin around the area. In severe cases, scabs or crusty patches can develop as the skin tries to repair itself.

These spots may also have areas of hair loss.

Because dogs with hot spots often bite or chew their skin, hair loss may develop as well. Hot spots often develop in areas where the dog has been scratching, chewing, or licking excessively. This repetitive activity can cause the fur to fall out, creating bald spots and areas of thinning fur.

One feature you can also notice in some cases is the moist, oozing sores of your dog’s hot spot.

The skin can produce a clear or yellowish discharge, and you may notice a scab forming around the edges as the body tries to heal itself. When this happens, you may notice a strong, unpleasant smell coming from the area.