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Armpit Rash on Dog: Our Vet Shares Top Reasons & What to Do

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vet examining a dog's armpit for possible rash

This article was updated on September 1st, 2023

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The skin is your dog’s largest organ, so it’s no wonder that it has its fair share of problems. One of the most commonly seen skin issues seen by veterinarians is rashes. Skin rashes come in all shapes, sizes, and locations. Here, we’ll focus on one specific area, the armpit rash.

What armpit rash is on dogs

dog with severe case of armpit rash

As a pet owner, it’s natural to worry when you notice something unusual about your furry friend. One occasional issue that dogs may experience is a rash in their armpits. These rashes are uncomfortable for your pet and concerning for you. The good news is with appropriate veterinary attention, they can be easily treated. In this article, we’ll take a closer look at armpit rashes in dogs, including their causes, symptoms, and treatments. By the end, you’ll be better equipped to recognize and respond to this common condition in your own furry companion.

What are the top reasons for armpit rash on dogs?

A dog’s armpit rash can have a variety of causes, but it’s pretty easy to recognize. Behind or under your dog’s elbow (where their front leg attaches to the chest), the fur is thinner and the skin softer than in most other areas of the body. A rash is present when the skin in this area is reddened, bumpy, or perhaps swollen. Rashes can also be itchy. The area may be moist or greasy if infection is present, or it may be dry and flaky if caused by a chemical, plant, or allergy. Armpit rashes are limited to the area under the front leg.

1) Physical irritation: Especially when frequently wearing a harness or clothing, armpit irritation is common. The simple solution is to discontinue the use of or exposure to the material, after which resolution should be quick. Dogs that are overweight and have excess skin rolls may have irritation rashes in the armpit from their skin rubbing together. Of course, the treatment is weight loss.

2) Contact dermatitis: While relatively rare, this skin reaction occurs when a dog comes into contact with an irritating substance, such as a chemical or plant. You may be able to manage it by gently washing the area with warm water and a cloth. If it’s persistent or gets worse, your pet’s best chance at quick recovery may be a visit to their veterinarian.

3) Allergies: Dogs can develop allergies to a variety of substances, including certain foods, environmental allergens, and flea bites. Allergies are increasingly common, though often mild, and can cause skin inflammation and itching, which can lead to a rash. While allergies can’t be cured, and will affect your dog long term, management of a skin rash from allergies is possible with allergy and anti-inflammatory medications.

red skin allergy symptoms in dog

4) Grooming/ Cleanliness issues: More common in longer-haired dogs than short-haired dogs (though not exclusive), rashes from matting or poor grooming practices occur when a dog’s fur becomes matted and tangled or there is trapped dirt and debris in the area. These contribute to skin friction or chafing that can lead to a rash and other issues. Proper grooming is great prevention. If a problem is already present, removing the mat or cleaning the area could improve or even resolve the armpit rash within a couple of days or weeks. If a secondary infection is present, a visit to the vet is in order.

5) Fungal or bacterial infections: These can occur when bacteria or fungi enter a dog’s skin through a cut, scratch, or other skin damage. Quick recovery is likely with appropriate veterinary care.

red and black dog skin due to a skin infection
Red rash as a result of a skin infection

Early symptoms to look out for 

Early warning signs of an armpit rash in dogs may include redness, swelling, or itching in the armpit area. You may notice your dog scratching or licking at their armpit more than usual, or that they seem uncomfortable. In some cases, the skin in the armpit area may be warm to the touch or feel moist or greasy. If you notice any of these symptoms in your dog, keep a close eye on the area and consult with your veterinarian if the symptoms don’t improve or if you notice any other concerning changes.

Treatment options for armpit rash on dogs

While some armpit rashes require veterinary care, mild cases can potentially be managed at home with a few simple interventions.

1) Keep the area clean and dry: Clean the affected area with a gentle pet-safe cleanser and warm water, then pat it dry with a clean towel. This can help to prevent bacteria and fungi from multiplying and making the rash worse. This can also reduce physical irritants like dirt, debris, plant material, or allergens on the surface of the skin.

2) Apply a cool compress: After cleaning, apply a cool, damp cloth to the affected area.

3) Use a pet-safe anti-itch spray or cream: There are several over-the-counter anti-itch sprays and creams available for dogs that can help relieve itching and discomfort. Choose a product that is specifically formulated for dogs and follow the instructions carefully. Because ingestion of these topical medications can be hazardous, monitor closely and apply a “cone” (e-collar, Elizabethan collar) or other protective device to keep your dog from reaching the area while being treated.

Product Recommendation – spray:

Vetericyn Plus Hot Spot Spray for Dogs Skin...
  • DOG HOT SPOT CARE: Spray a few times daily to relieve irritated skin that cause excessive scratching, chewing, and licking.

Product Recommendation – inflatable collar:

BENCMATE Protective Inflatable Collar for...
  • ✅ 【COMFORTABLE FOR YOUR PET】 - While wearing the BENCMATE Collar, the inflatable function and the soft outside material will let your dog wear it comfortably and it does not block your pet’s vision, they can eat, drink, sleep and play at ease while staying protected.

4) Switch to a different type of harness or clothing: If you suspect the rash is caused by contact with a harness or other type of clothing, try a different material or style that doesn’t rub against the skin in the same way.

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Product Recommendations – alternate harness:

PetSafe Easy Walk No-Pull Dog Harness - The...
  • HELPS STOP PULLING: Patented Martingale loop design puts gradual pressure on your dog’s shoulders to safely and effectively stop pulling; a front leash attachment helps you guide your dog
PetSafe EasySport Dog Harness, Adjustable...
  • GREAT FOR ACTIVE DOGS: Best harness for running, walking and hiking with your active dog

These home interventions are only appropriate for mild cases that show signs of improvement with early intervention. If the rash is severe or doesn’t improve with home care, consult with your veterinarian for evaluation and treatment.

Disclaimer: This content is not a substitute for veterinary care. Always consult with your vet for health decisions. Learn more.

Frequently Asked Questions

Can an armpit rash on dogs be contagious?

Armpit rashes on dogs are often caused by a variety of non-contagious factors such as allergies, infections, or poor grooming. However, in rare cases, certain infections that cause skin rashes, such as ringworm, can be contagious. It’s always best to consult with your veterinarian to determine the cause of your dog’s rash and whether or not it is contagious.

How long does it take for an armpit rash on dogs to heal?

The healing time can vary depending on the cause and severity of the rash. Mild cases may clear up within a few days to a week with proper treatment and care. More severe cases could take several weeks or longer to heal. Closely monitor your dog’s rash and consult with your veterinarian if it doesn’t improve or if it gets worse.

Can armpit rash on dogs be a sign of a more serious condition?

While armpit rash on dogs is typically a mild condition that can be easily managed with proper treatment and care, it can sometimes be a sign of a more serious underlying condition. In some cases, armpit rash may be a symptom of an underlying allergy, autoimmune disease, or hormonal imbalance. Consult with your veterinarian if you notice concerning symptoms or if the rash doesn’t improve with treatment.


  • Dr Chyrle Bonk, Veterinarian

    Dr. Chyrle Bonk received her Master in Animal Science from the University of Idaho and her Doctorate of Veterinary Medicine (DVM) from Oregon State University in 2010. She has over 10 years of experience in small animal veterinary practice, working for a veterinary clinic in Idaho.

  • Kate Howard, Vet Tech

    Kate Howard lives in Upstate New York, and received her degree in Veterinary Technology from Alfred State College of Technology in 2010. She has been a veterinary technician for 13+ years, and spent her career working primarily in general practice and veterinary emergency care. Kate has 3 dogs, a cat, and keeps a small flock of backyard poultry.

Disclaimer: This website's content is not a substitute for veterinary care. Always consult with your veterinarian for healthcare decisions. Read More.


  1. Hello, I appreciate learning more about the rash under the armpit. I was wondering if cornstarch or possibly diaper rash medication would be safe to apply to the rash? Such as desinex. Thank you, Janet Henry

    • Hi there Janet,
      I would personally not use either of these products. Some owners use cornstarch as it can help to dry out oozing and feels cool. Diaper rash medicine can contain zinc oxide which is toxic. I’d usually bathe the rash with either salt water or a dilute solution of Hibiscrub, however treatment really does depend on what exactly we are dealing with.
      Dr Linda Simon MVB MRCVS
      “The information on this website is not a substitute for in-person veterinary care. Always seek advice from your veterinarian if you have concerns about your pet’s medical condition.”

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