Symptoms of Dermatitis in Dogs

Dermatitis in dogs causes them to frequently scratch and bite themselves, sometimes to the point where skin becomes raw or patchy. Dermatitis in dogs is a skin disorder caused by any number of conditions that can be diagnosed by different symptoms. Flea allergies, or allergic reactions to other substances, bacteria or direct contact with a caustic or toxic substance can all cause dermatitis in dogs. While causes of this disorder are many, symptoms are few and generally easy to detect.


Many different symptoms of dermatitis in dogs may reveal themselves depending upon the underlying condition causing the dermatitis. Persistent scratching, itching and biting is the most common symptom of dermatitis. Most types of dermatitis will cause a dog to relentlessly scratch or bite a particular area of the skin, and often open wounds will reveal themselves rapidly.

Hot Spots

The sudden appearance of a red or sore looking spot on the skin may be another sign of dermatitis in dogs. Often, bacteria or allergies cause the dog to lick profusely at a particular spot on the skin. Licking or biting one spot for a prolonged period of time will cause the skin to break open. Bacteria can then spread into open skin areas causing additional redness, soreness, itching and infection. The appearance of hot spots is more common in warm or humid weather and usually results from a flea bite, allergic reaction or contact with a toxic substance.

Loss of Hair; Mange

Mange is detected by loss or hair or scabby eruptions on the skin. Dogs contract mange from parasitic mites that are transmitted by other affected dogs. These mites embed themselves into the skin or hair follicles and cause inflammation, loss of hair and scabs or areas of pus. Mange commonly spreads to the dog's abdomen, chest, ears and legs and is a source of severe irritation for the dog.

Ear Infections or Head Shaking

Often, advanced cases of dermatitis in dogs will produce additional symptoms in conjunction with scratching, biting or redness on the skin. Ear infections are a common symptom. If skin irritation has spread into the ears, the dog may begin to obsessively scratch and dig at and inside the area. This may cause open sores to develop inside the ears, which then will lead to ear infection. Dogs may begin to shake their heads, and continue scratching due to the pain and itching now caused by the infection.

Other Symptoms

Due to severe and persistent itching caused by dermatitis in dogs, this condition can lead to other symptoms directly or indirectly related. Runny nose or watery eyes may result from infections caused by mites, allergies or other toxins. Depression or loss of appetite may ensue. Changes in skin pigment, texture, or the appearance of red bumps, pus vesicles or lesions may also be symptoms of dermatitis in dogs. Allergies or reactions resulting in dermatitis may weaken the immune system, leading to other complications if not treated.