Rashes and Hives (Urticaria) in Dogs

Urticaria is considered to be relatively uncommon in dogs. Any breed can be affected although dogs with short or light colored hair are more likely to be diagnosed. Urticaria is usually not of grave concern for pet owners. Most commonly, the allergen can be identified and avoided and the symptoms thereby can be effectively managed. In rare cases, if there is swelling in the mouth or airways the dog will need immediate veterinary care to avoid suffocation.

Urticaria is the dog’s immune system response to contact with a chemical or allergen that results in red, itchy, patches or sometimes bumps on the skin.

Symptoms generally appear a few hours after your dog comes in contact with the allergen or chemical causing the allergic reaction. Symptoms will vary between dogs and allergens. The most obvious symptom is the red patches of skin or wheals that define the condition. They can be seen anywhere on the body but are most commonly found on the back, legs, flank, and neck. In more severe cases the eruptions may appear on the mucous membranes of the dog’s body. Other clinical symptoms for dogs suffering from urticaria include:

• Bumps on skin, face ears or tongue
• Difficulty breathing
• Swollen eyes or face
• Excessive scratching
• Drooling
• Fever
• Lethargy
• Anorexia

Types

Urticaria is not generally subdivided however, a couple of examples are worth noting.

• Anaphylactic -This causes swelling in the nose , mouth, and throat of the dog; this type of urticaria is potentially life threatening to the dog as the swelling could become so severe that the dog’s airway is blocked, causing suffocation
• Chronic -This happens when the allergen cannot be identified or removed from the living space of the dog
• Heat Reflex - This is an uncommon affliction wherein the dog suffers from heat rash

• Food allergies
• Chemical reaction (particularly to lawns treated with pesticides)
• Vaccinations (particularly rabies and bordetella)
• Toxic plants
• Inhaled allergens
• Stress
• Exercise
• Intestinal parasites
• Prolonged exposure to heat or sunlight
• Illness
• Milk retention (during female heat cycle)

Diagnosis of urticaria will require an accurate health history of your pet. The veterinarian may have an indication of what is causing the condition based on the symptoms you describe as accompanying the skin outbreak as well as the type of rash that is present upon examination. A picture of your pet’s skin at it’s worst will be a helpful diagnostic tool for the veterinary team in addition to skin scrapings that may be taken and analysed under the microscope.

Blood tests may be indicative of markers related to urticaria; a description of your dog’s diet, grooming aids, recently administered supplements, and possible exposure to plants that could be skin irritants will be helpful to the veterinarian. If allergies are suspected, testing may be done or an elimination diet may be suggested.

Hives will often disappear as fast as they come on while other rashes may linger and possibly cause distress for your pet. Sometimes Benadryl is administered to relieve symptoms. Benadryl, as prescribed by your veterinary caregiver, can also be used to prevent anaphylactic swelling. It is important to seek professional treatment in the case of anaphylactic swelling as the dog's  life may be in danger.

In more severe cases of urticaria, a steroid may be administered, particularly if your pet is finding the condition to be itchy. Secondary conditions are possible if the skin becomes excessively red or raw.

Because hives are typically self-limiting recovery and the prognosis is usually great. In severe cases, if there is swelling in the mouth or airways, the dog will need medical intervention to be able to breathe. Keeping Benadryl in the household can help especially if the allergen remains unidentified. Removing common allergens or pesticides from the home is advised.

The most common food allergens for dogs are chicken, wheat, and beef. There are tests available from your veterinarian that can list your dog’s food allergens, in order of severity. Otherwise, you may choose an elimination diet to determine the allergen. Most dogs see dramatic improvement after eliminating chicken from their diet due to some processing methods of chicken in dog food. A diet focused on fish proteins may help soothe and restore the dog’s skin no matter what the allergen. Adding fish oil to your dog’s diet can also help.