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Key takeaways

Rash is defined as an eruption on the skin in dogs.

  • This may appear as reddened skin, hair loss, scabs, moist, pruritic (itchy) spots with pus, bumps, raw patches, sores, scales, or thickened, crusty skin
  • Rash can be caused by any factor that causes irritation or inflammation of the skin
  • The most frequent causes of rashes in dogs are allergies and bug bites
  • Rash can be identified by a visual identification, but the underlying cause is needed to determine the appropriate treatment
  • Tests may include skin scraping, skin culture, and skin biopsies
  • Treatment varies depending on the underlying cause and can range from topical ointments to systemic medications to surgery
  • Treatment and/or management of the underlying cause is important as recurrence is common
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A closer look: Rash in Dogs

Rashes are very common in dogs, and are almost never an emergency on their own. When a rash is accompanied by difficulty breathing, profuse vomiting, or collapse, this is an emergency and could be a sign of anaphylaxis.

Rash can be secondary to many conditions, such as hypothyroidism, Cushing’s disease, allergies, autoimmune disease, and cancer. If a rash gets worse or does not go away after one week, veterinary attention is warranted.

Possible causes

A rash is generally due to inflammation, irritation, or a defect in the skin.

Risk factors

Rash varies widely in severity and can range from slightly reddened skin to weeping sores. Some rashes can spread to encompass larger areas of skin, be itchy, purulent (pus-filled), and foul-smelling. Hair loss may be observed with hypothyroidism, welts with allergic reactions, and purulent exudate with hot spots.

Testing and diagnosis

Visual examination can help diagnose a rash, but testing is necessary to determine the underlying cause. Diagnostics include skin cytology to check for microorganisms, blood tests to check for underlying metabolic disease, biopsies to rule out cancer, and allergy testing.

Treatment varies widely depending on the underlying cause of the rash. Examples include oral antibiotics, anti-inflammatories, antiparasitic medications, topical ointments, antihistamines, antifungals, anti-itch medication, and surgical removal of lesions.

Similar symptoms

A swelling under the skin may be mistaken for a rash.

Associated symptoms


Katie Grzyb, DVM - Writing for PetMD
Krista Mifflin - Writing for The Spruce Pets
Jean Marie Bauhaus - Writing for Hill's Pet Nutrition
Becky Lundgren, DVM - Writing for Veterinary Partner
The VIN Dermatology Consultants - Writing for Veterinary Partner
Karen A. Moriello, DVM, DACVD - Writing for Merck Veterinary Manual

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