Dermatitis in Dogs

Dermatitis is a catchall term for the numerous inflammatory skin diseases that can affect dogs. These may be transient or chronic, often affecting the overall health and sheen of the coat.

Types of dermatitis in dogs
Persistent itching is a very common, nonspecific sign of dermatitis in dogs and cats. Many conditions may cause dermatitis and prompt an affected animal to scratch or bite itself frequently. Causes of dermatitis include:

• bacterial, fungal, yeast, or parasitic infection
• seborrhea
• food allergies or sensitivities
• flea bites (flea saliva is a common allergen)
• contact with an irritating substance
• metabolic and endocrine disorders
• drug reactions; exposure to toxins
• breed-specific predisposition
• nutritional deficiencies
• sunburn
• cancer may give rise to excessive itching due to skin irritation

Canine atopy Atopy is a common cause of chronic itching in dogs. (It is believed to affect 15% of dogs in North America.) Canine atopy is caused by an allergic reaction to one or more substances in the environment, usually grass, and commonly starts between the ages of one and five years. The genetic makeup and environment contribute towards development of the disease, which is due to a failure of the immune response.
Dogs that have atopy usually itch and so scratch a lot, which can cause red, moist, irritated skin. The face and feet are most commonly affected but ear infections are also common. Sometimes, dogs with atopy will also have runny eyes or nose.

Pyotraumatic dermatitis Often referred to moist dermatitis or a “hot spot,” pyotraumatic dermatitis manifests as a red, moist, hairless, painful-looking sore that appears suddenly.
Thick-coated, longhaired dog breeds, such as golden retrievers, Newfoundlands, German shepherds, and Bernese mountain dogs are particularly susceptible to hot spots. The raw areas develop when something causes such severe itching or irritation that a dog scratches and licks his skin raw. Often, this licking and scratching goes on at night, so the sudden appearance of the sore can be an unpleasant surprise for a pet owner.
Hot spots are caused by bacteria that naturally inhabit the surface of the skin. They develop when incessant scratching and biting damage the skin enough to break down its barrier function (primary non-specific immunity). The bacteria then proliferate, causing more irritation. Hot spots frequently develop at the site of a flea bite but may result from allergic reactions, ear infections, and other irritants. They are more common in hot, humid weather

Canine acral lick dermatitis Acral lick dermatitis, sometimes called lick granuloma, is a fairly common skin condition in dogs. Affected dogs usually spend a considerable part of their day licking at one particular spot on one leg. An infected, wound eventually arises at the site.

Contact dermatitis Contact dermatitis is a skin disorder that may develop after direct contact with certain materials such as:

• caustic or corrosive substances such as bleach
• strong acids or alkalis and salt are the main culprits
• fertilizers
• carpet cleaners
• flea collars

Contact dermatitis may also develop when a pet becomes sensitive to a substance that is normally not an irritant, such as bedding material.
Contact dermatitis may cause itchy, red skin over the parts of the body that have been exposed to the irritant.

Flea allergy dermatitis This condition affects dogs and is characterized by severe, unremitting itching. It is caused by a sensitivity to the saliva of fleas. Just one flea bite can cause intense misery to an affected animal. Even minimal or intermittent exposure to fleas can give rise to the condition. Dogs with flea allergy dermatitis may lose hair in the affected areas and develop hot spots over the haunches and tail. Cats may groom themselves excessively and may lose hair over their backs.

Canine sarcoptic mange Canine sarcoptic mange, an extremely irritating condition, is caused by the Sarcoptes mite. While Sarcoptes can affect any area of the skin, canine sarcoptic mange most often affects a dog's abdomen, chest, legs, and ears. Mites are usually transmitted when a dog comes into contact with an infected dog, or area where another infected dog has been. (The mites can survive for up to three weeks in the environment.)

Feline notoedric mange Feline notoedric mange is similar to canine sarcoptic mange. Notoedres cati is a microscopic mite that infests the skin of cats. The mite gives rise to an itchy, frequently crusty skin condition that typically affects the ears, face, and neck.

Symptoms and diagnosis of dermatitis

The following conditions are symptomatic of dermatitis in dogs:

• Persistent scratching.
• The appearance of a red, painful-looking sore (hot spot), often overnight.
• Scaly, rough or oozing areas on the skin, usually accompanied by hair loss

Treatment options for dermatitis in pets

Since dermatitis is likely to result from an allergy or other ongoing irritant, the animal’s lifestyle, food intake, etc. should be reviewed closely and discussed with the pet owner. If the dermatitis results from an allergic reaction to flea bites, action should be taken to rid the home of fleas.
Corticosteroids such as injectable dexamethasone will help calm the itching and inflammation resulting from dermatitis.; however, safer and more natural approaches may be more suitable.
If a hot spot has developed, it should be treated promptly to prevent infection. Oral antibiotics, and a few days treatment with oral corticosteroids will normally clear up the affected area. Again, safer and more natural approaches may be more suitable.