What Are the Most Common Causes of Rashes on Dogs?

Kaiser Castro

Fleas, allergies, infections, and contact dermatitis are all common causes of rashes on dogs. Poor nutrition can also aggravate skin problems. Excessive scratching can break the skin, creating an opening for a secondary infection that can aggravate the ailment. Dogs that scratch excessively should be taken to a veterinarian for a diagnosis.

Fleas can cause rashes on a dog.
Fleas can cause rashes on a dog.

One common reason why a dog might be excessively scratching, creating red patches and a rash, is due to fleas. Fleas are highly contagious, easily passing to other pets. The fecal matter from the fleas act as the agent that causes rashes on dogs, as well as the actual biting from the fleas. Infected areas tend to be sore, red, and bare of hair due to the scratching. Fleas, however, can usually be easily managed with the help of medication.

Allergies are a common cause of rashes on dogs.
Allergies are a common cause of rashes on dogs.

Allergies are another cause for skin rashes on dogs. As a dog brushes against plants or grass, some of the pollen will stick onto the fur or skin. An allergic dog can experience skin irritation. Hives are another common symptom of an allergic response; the hives will usually be circular in shape, sometimes protruding from the skin. Dog shampoos formulated with oatmeal can help with skin irritation.

Broken skin due to the scratching can lead to bacterial infections, causing skin rashes. Internal infections can also cause external rashes on dogs. Scratching can spread the infection to other areas, worsening the problem. Bacterial infections tend to be more robust, and will usually require medication from a veterinarian to be controlled and cured.

Contact dermatitis is caused by surfactants, cleansers, and chemicals that can cause discomfort to the dog. Excessive shampooing, for example, can dry out the coat and skin, causing rashes on dogs. Canine dermatitis can also occur when the dog becomes irritated with material that it would normally not be reactive to, like bedding material. Monitoring the dog's lifestyle is important to eventually remove the substance or chemical that is causing the dermatitis.

Poor nutrition can lower the skin's defenses against skin disorders. Mineral deficiencies can alter the skin and fur as well, creating an environment for a skin ailment to develop. A dietary supplement formulated with essential fatty acids can help support healthy skin development and lower the chances of rashes on dogs from occurring.

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Discussion Comments


From my experience, dogs are more prone to rashes in the hot summer months. Insects, plants, and extreme heat can all contribute to this pesky skin problem that can cause dogs to scratch constantly. This creates a vicious cycle that only makes the problem worse.

I have found that frequently bathing your dog in the summertime helps reduce the risk of him developing a rash. When itchy irritations do occur, wiping them clean with an antiseptic helps prevent infections. Finally, I have also found that using a medicated powder on irritated areas helps keep the rash dry, and decreases the chance that it will spread to other parts of his body.


@talentryto- If you haven't taken your dog to see a veterinarian already, you should do this first. He or she will be able to diagnose the issues that are causing your dog's reoccurring rash.

I have had dogs that have had this problem, and my vet has prescribed a variety of treatments at one time. Antibiotics help control any secondary infections caused by the rashes, anti-itch creams control the itching, and a variety of medications targeted to my dogs' specific problems help to make the rashes go away and prevent them from returning. Of course, flea preventative helps to control itching and a variety of rashes, and can be given with other types of medications.


I have a dog that has a reoccurring rash, and his usual treatment of medicated baths and cortisone ointment is no longer working. Does anyone have any suggestions of a better method for treating his problem?

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