Contact Dermatitis in Dogs: Symptoms, Common Causes, and Treatment

Contact dermatitis in dogs is a skin reaction that occurs when your dog’s skin comes in contact with an irritant known as an allergen. 

These allergens are typically protein molecules (from fabrics, plants, or other substances) that trigger an immune response, which leads to symptoms like itching, redness, crusting, and pustules on the skin. 

Your vet can help you identify the trigger and recommend the best treatment to control inflammation and itching. 

What Is Contact Dermatitis in Dogs?

Contact dermatitis is a localized inflammatory skin reaction caused by direct exposure to an irritant (irritant contact dermatitis) or an allergen (allergic contact dermatitis). 

Unlike environmental or seasonal allergies that cause generalized itching, contact dermatitis typically appears where the skin made contact with the trigger. 

Contact dermatitis is a relatively uncommon skin condition in dogs, primarily because of the protective barrier provided by their fur coat. As a result, most symptoms develop on the parts of the dog’s body that have no hair or sparse hair and include: 

• The webbing between the toes 

• The muzzle 

• Around the eyes 

• Armpits 

• A dog's pressure points (elbows, ankles) 

• Belly 

• Groin 

• Scrotum 

• Rear end 

Symptoms of Contact Dermatitis in Dogs

The symptoms of contact dermatitis will often come and go depending on the duration and timing of contact with the allergen. Common symptoms include: 

• Red and inflamed skin 

• Hair loss 

• Hardened scales, flakes, and scabs 

• Darkened skin 

• Pustules or pimples 

• Itchiness and scratching 

While localized skin irritation in dogs is not considered a medical emergency, there is still a risk that open sores may become infected, symptoms will get worse, and your dog will generally be uncomfortable due to persistent itchiness and scratching.  

If you suspect your dog has skin allergies that are causing contact dermatitis, take them to your veterinarian. 

Causes of Contact Dermatitis in Dogs

Contact dermatitis is caused by an allergic reaction that occurs when your dog’s skin encounters an allergen. 

Some of the most common substances that can trigger contact dermatitis in dogs are: 

• Plants 

• Detergents 

• Mulch 

• Rugs and carpet 

• Fabrics 

• Plastics 

• Concrete 

• Medications 

• Chemicals 

• Fertilizers 

This contact triggers a local immune response in which your dog’s immune system identifies the allergen as a threat, even if it’s harmless. Instead of ignoring the substance, the dog’s immune system inappropriately overreacts and produces antibodies to fight off the “invader.” In turn, these antibodies trigger inflammation and symptoms.

Contact dermatitis can affect dogs of any breed, gender, and age, provided that the dog is older than six months. Dogs who already have allergies may experience more severe or frequent flare-ups.  

How Veterinarians Diagnose Contact Dermatitis in Dogs

Typically, the distribution of skin lesions on areas that touch the ground or other surfaces, such as the face, paws, belly, and rear end, are often enough to raise suspicion that your dog has contact dermatitis. 

If the trigger is unclear, your vet may recommend patch testing. This process typically involves shaving the hair on your dog’s side—usually a couple of days beforehand—and applying small amounts of the suspected allergen (such as plant material) directly to the skin. Any resulting response (with symptoms like those described above) is noted by your vet within a few days after the application. 

Alternatively, your vet may recommend avoiding a suspected allergen for about a week, followed by a “rechallenge.” During the rechallenge, your dog will be exposed to the suspected allergen again to see if it triggers a response. 

Because dogs with other types of skin disease usually have similar symptoms, your veterinarian may recommend additional tests, such as: 

• A skin impression (pressing a glass slide on your dog’s skin to then examine under a microscope) to screen for infection with yeast, bacteria, and white blood cells 

• Skin scraping to screen for infection with mites 

• Fungal testing (including a Wood’s lamp examination, fungal culture, or fungal PCR) to check for infection with ringworm 

• A biopsy to rule out more serious skin conditions like pemphigus or cancer 

In complex or persistent cases, a consultation with a veterinary dermatologist may be required.   

Treatment of Contact Dermatitis in Dogs

Contact dermatitis can be managed at home, but depending on the level of skin disease and itching involved, your dog may require prescription-strength medication. 

Anti-Itch Medications 

For dogs with active symptoms, your vet may prescribe medications to help control the itching, such as Zenrelia. Zenrelia is a prescription medication designed specifically to control itching caused by allergic dermatitis in dogs over 12 months of age. The single daily pill offers rapid relief and can be used for as long as your dog has symptoms. 

Depending on your individual pup, your vet may recommend other prescription medications to control itching, like Apoquel tablets or Cytopoint injection.

Medications to Treat Secondary Infections 

If a secondary bacterial or yeast infection is present, treatment may involve prescription antibiotic or antifungal medications.

Often, an antibiotic injection, such as Convenia, or oral antibiotic medications, such as Rilexine, Simplicef, or Clavamox, are used alongside oral antifungal medications like fluconazole or ketoconazole. 

Topical Therapies 

Topical therapies—including ointments, shampoos, and conditioners containing antibacterial, antifungal, and/or steroidal properties—may also be prescribed.

Bathe your dog under the guidance of your veterinarian. This can lessen your dog’s symptoms, help the skin infection heal faster, reduce the need for oral antibiotics or antifungal medications, and make your pup more comfortable and feel less itchy sooner. Your vet may recommend using medicated or hypoallergenic shampoos. 

Supplements and Diet 

Your vet may recommend omega-3 fatty acid supplements, which support a healthy skin and coat. 

Additionally, specialized diets designed to strengthen the skin barrier, soothe, and nourish a dog’s skin, and support their immune system—such as Hill’s Derm Complete—could be helpful. 

Consult with your veterinarian to determine the best medications, topicals, supplements, and diet for your dog, considering their unique medical and nutritional needs.

Recovery and Management of Contact Dermatitis in Dogs

The prognosis for dogs with contact dermatitis is often good if the allergen is identified and avoided. Most dogs begin to improve quickly after appropriate treatment is started, especially when itching and inflammation are controlled early.  

In mild cases, noticeable improvement often occurs within three to seven days. Moderate cases may take one to two weeks to fully resolve, particularly if prescription medications are needed. 

Prevention of Contact Dermatitis in Dogs

Contact dermatitis can be challenging to treat. Prevention is the best way to help your dog avoid uncomfortable symptoms. 

Avoiding contact with the allergen whenever possible is key, which may involve measures such as: 

• Removing carpeted areas or rugs 

• Removing plants and weeds 

• Using HEPA filters 

• Changing your dog's water or food bowl 

• Barrier methods like recovery cones or T-shirts—as well as more frequent bathing with or without leave-in shampoos and conditioners—may be helpful.