What does infected skin on a dog look like?

Dog skin infections are relatively common and can have a variety of causes. Recognizing the signs of an infected skin condition on your dog is important for getting prompt veterinary treatment. This article provides an overview of what infected skin on a dog looks like, common causes, symptoms to watch for, and when to seek veterinary care.

Table of Contents

What Causes Skin Infections in Dogs?

There are several potential causes of skin infections in dogs:

Bacterial infections – Staphylococcus, Streptococcus and Acinetobacter bacteria are common causes. Hot spots and pyoderma are examples of bacterial skin infections.
Fungal infections – Ringworm, yeast and mold can infect a dog’s skin.
Parasitic infections – Mites, lice and ticks can lead to skin irritation and secondary infections.

Allergic reactions – Food allergies, environmental allergies and flea allergy dermatitis can cause itchy skin susceptible to infection.
Underlying conditions – Hypothyroidism, Cushing’s disease, autoimmune diseases and cancer can make dogs prone to skin infections.
Trauma – Broken skin from scratches, cuts or wounds can allow bacteria to enter and cause infection.

In most cases, there is an underlying cause or condition that allows normal bacteria or fungi that live on a dog’s skin to multiply and cause infection. Treatment involves addressing both the infection and the underlying problem.

What Does Infected Skin Look Like on a Dog?

There are several characteristic signs of a skin infection in dogs:

Redness – The skin may turn red and inflamed around the infected area.

Pustules and papules – Small, pus-filled bumps or pimple-like lesions on the skin.
Crusts or scabs – Thick crusty patches or scabs may form over infected areas.
Hair loss – Patches of hair loss or bald spots often occur in infected areas.

Odor – There may be a foul odor coming from infected skin.
Dampness or oozing – Wetness and fluid drainage can occur if pustules rupture.
Scaliness – Flaky, scaly skin may be present.

Ulcers – Open sores or ulcers can develop in some cases.

The appearance can vary depending on the type of infection. Fungal infections often cause circular patches of hair loss. Bacterial infections may result in pus-filled pimples. Parasitic infections can lead to redness, itching and scaly skin.

Common Skin Infection Symptoms in Dogs

In addition to how the skin looks, dogs with skin infections often display other symptoms and behavioral changes. Signs to watch for include:

Itching and scratching – Skin irritation causes affected dogs to compulsively lick, bite, rub or scratch at their skin.
Aggressive licking – Dogs may spend hours obsessively licking infected areas.
Hair loss – Scratching and licking leads to patches of hair loss.

Redness – The skin appears reddened and irritated.
Scabbing and crusting – Blood and fluid from scratching leads to scab formation.
Odor – The infected area often smells bad.

Swollen lymph nodes – The lymph nodes may be enlarged near the infected skin.
Lethargy – Dogs with skin infections may seem tired and inactive.
Depression – They may be depressed or mopey due to discomfort.

The location of symptoms on the dog’s body can sometimes provide clues to the cause. For example, fungal infections often affect the paws first. Allergies tend to cause itching on the face, feet, ears and abdomen.

When to See a Veterinarian

It’s important to have your dog examined right away if you notice signs of a possible skin infection. Early treatment improves the chances of a good outcome and prevents complications. Seek prompt veterinary care if your dog shows:

Pustules, papules, crusts or ulcers on the skin

Redness, hair loss or scabbing
Constant itching, licking or scratching
Foul odor coming from their skin or coat

Loss of appetite or lethargy

Skin infections left untreated can worsen and spread to other areas of the body. Bacteria and fungi can enter the bloodstream and cause serious systemic illness in dogs. Any skin problem that persists or worsens despite home treatment warrants medical assessment.

Diagnosing Skin Infections in Dogs

To diagnose the cause of your dog’s skin infection, the veterinarian will begin with a thorough physical exam of your pet. They will closely inspect all areas of the skin, noting the location, appearance and distribution of lesions. Areas of hair loss, crusting, scaling and discharge will be identified.

Your vet will also ask about your dog’s health history and when symptoms began. Underlying conditions that could predispose your dog to infection will be considered. Diagnostic tests that may be performed include:

Skin scrapings – Microscopic examination of skin cells and debris to identify parasites, fungi or bacteria.
Skin cytology – Microscopic evaluation of cellular material from the skin.

Bacterial culture – Growing bacteria from a skin sample to identify specific pathogens.
Fungal culture – Growing a skin sample to identify fungal organisms.
Skin biopsy – Microscopic examination of a small skin sample taken under anesthesia.

Blood tests – Analysis of blood samples to look for underlying causes such as thyroid problems.

Once your vet determines the type of infection present, they will prescribe appropriate treatment. Most skin infections are curable with prompt medical therapy.

Skin Infection Treatment for Dogs

Treatment of skin infections aims to eliminate the underlying cause, clear the infection, relieve symptoms, and prevent recurrence. This usually involves a combination of topical and systemic therapies such as:

Antibiotics – Oral or topical antibiotics prescribed for several weeks to clear bacterial infections.
Antifungals – Oral, topical or shampoo medications that kill fungal infections.
Antiparasitics – Medicated dips, shampoos, collars or pills to kill parasites.

Medicated shampoos and rinses – Used to kill pathogens and soothe inflamed skin.
Anti-itch shampoos and sprays – Provide relief from itching and irritation.
Corticosteroids and antihistamines – Help stop itching caused by allergies.

Topical therapy – Ointments, creams or gels applied to treat infected skin lesions.
Bandaging and protective devices – Prevent licking, scratching, and further infection.

Identifying and eliminating underlying allergies or conditions causing skin infections is also extremely important. This may involve hypoallergenic diets, flea control, thyroid medication, or treatment of Cushing’s disease.

In severe cases, hospitalization for intravenous antibiotics, fluids and wound management may be necessary. Surgery is sometimes needed to remove necrotic tissue or drain deep skin abscesses.

Home Care for Skin Infections

To support your dog’s treatment and recovery from a skin infection:

Give all medications as prescribed by your veterinarian.

Use an Elizabethan collar to prevent licking and chewing at infected skin.
Gently cleanse skin lesions daily with an antiseptic rinse recommended by your vet.
Apply prescribed topical ointments thinly to affected areas 1-2 times daily.

Bandage wounds if needed to prevent trauma and contamination.
Wash bedding frequently to prevent reinfection.
Bathe your dog weekly with a medicated shampoo until resolved.

Closely follow your veterinarian’s advice for bathing and bandage changes. Allowing your dog to swim or soak infected skin before it has healed can worsen infections. Strict rest is required for some dogs until the skin infection has improved.

Preventing Recurring Skin Infections

Once a skin infection clears in a dog, measures should be taken to prevent recurrence. Suggestions include:

Treat any underlying condition, like hypothyroidism or Cushing’s disease.

Investigate and control for environmental allergies.
Eliminate parasites such as fleas and mange.
Test for food allergies and feed an appropriate diet.

Keep skin folds clean and dry, especially in wrinkly dogs.
Promptly treat any trauma, cuts or wounds.
Improve grooming and hygiene of longhaired dogs.

Use antibiotics long term if your dog has recurring infections.
Get monthly skin scrapings to check for mites.

Dogs with weak immune systems or endocrine disorders may need lifetime management to prevent skin infections returning. Follow your veterinarian’s recommendations to identify and reduce risk factors unique to your dog.

When to Seek Emergency Care

Skin infections can progress and worsen rapidly in some cases. Seek emergency veterinary care if your dog shows any of the following:

High fever
Depression, lethargy or weakness

Loss of appetite
Vomiting or diarrhea
Fast, labored breathing

Yellowing of the skin or gums
Skin redness, swelling or ulceration spreading quickly
Pus-like discharge from multiple skin areas

Skin infection unresponsive to treatment

These signs can indicate the infection is progressing into a systemic illness or life-threatening condition like sepsis. Urgent medical care is needed to stabilize your dog and provide intensive antibiotic therapy.

Prognosis for Dogs with Skin Infections

The prognosis for dogs with skin infections depends on several factors:

The type of infection – Bacterial infections tend to respond better than fungal infections.
How soon treatment was started – Early treatment leads to better outcomes.
The presence of complications – Sepsis, tissue necrosis and organ failure worsen the prognosis.

The underlying cause – Control of predisposing conditions is key.
The immune status of the dog – Weakened immunity makes recovery more difficult.
The dog’s overall health – Young, otherwise healthy dogs have better healing ability.

With appropriate veterinary treatment and follow up care, most superficial localized skin infections resolve without complications. However, severe, deep-seated or neglected infections can be life threatening. Recurring infections are likely if underlying causes are not addressed.

Conclusion

Skin infections are common in dogs and can arise from bacteria, fungi or parasites. Infected skin typically appears red, scaly and crusty with hair loss and papules or ulcers. Itching, odor and discharge are also common. Prompt veterinary diagnosis and treatment improves the prognosis and prevents complications. Controlling underlying causes, maintaining skin health and practicing good hygiene helps prevent recurrence.