From rash to scabs, here’s how to recognize the signs of common issues like mange, dermatitis, and allergies so you can treat the issue quickly.

By Lacey Howard
August 24, 2020
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Nehru Sulejmanovski / EyeEm / Getty

There are many times as pet owners when we wish our pups could talk, but we probably feel the desire most passionately when our furry friends are ill and in obvious discomfort. When skin conditions erupt, your dog’s misery and frustration can bring on behavior changes. He might lick [link to Why Dogs Lick article on DP], chew, and scratch himself obsessively. You may notice he’s lethargic and seems to have lost his get-up and go and his happy-go-lucky attitude. He may have a distinct odor or you may notice touching his skin causes him pain. Anne Conover, DVM, the owner of Rolling Hills Veterinary Clinic, a mixed animal practice in Madison County, Iowa, says, “Visual cues that your dog may have a skin condition can include hair loss or hair breakage; dull hair coat; reddened, discolored, or thickened skin; red bumps or sores on the skin; oiliness of the skin and hair; or rashes.”

While the various types of skin conditions that cause these symptoms are numerous enough to fill entire veterinary textbooks, there are some common diagnoses for pruritis (itchy skin). And while the descriptions below may give you an idea of what ails your pup, “most skin conditions cannot be diagnosed by visual appearance alone,” Conover warns. “And treatments vary widely depending on the underlying cause. This is a subject best discussed with your veterinarian after a thorough exam and necessary diagnostic tests.”

Dermatitis 

Dermatitis is a general term that simply means inflamed or irritated skin. And when we’re talking skin conditions, dermatitis is a symptom of your dog’s underlying issue—anything from fleas to an autoimmune disorder. 

A dermatitis diagnosis may have a specific cause such as bacterial dermatitis (or irritated skin caused by a bacterial infection), which results in circular patches of hair loss (called alopecia) and crusty patches on the skin and is treated with a course of antibiotics. Dermatitis with alopecia can also be caused by pests like fleas or mites or by fungal infections like ringworm, which is treated with antifungal medications and shampoos. 

Keep in mind that dermatitis is a major symptom of all of the conditions listed below.

Allergies 

There are two types of allergic reactions in dogs: systemic and contact. 

Systemic allergies affect the entire body and when they cause skin issues, the skin condition is called Atopic dermatitis. These system-wide allergic reactions can be caused by food, medication, or even environmental allergens such as grasses, pollen, or mold. 

Contact dermatitis is an allergic reaction caused by the dog coming in contact with something that causes skin irritation or an allergic reaction at the point of contact, such as an insect bite or poison ivy. 

If you think your dog is experiencing allergies, your vet can help identify and eliminate the offending substance and suggest an appropriate treatment. Sometimes, it can be as easy as changing his dog food. Other times, however, “This can be a long, frustrating process—for the owner, the dog, and the veterinarian!” Conover says. In this case, she says, the vet will offer “symptomatic relief to control the itching while trying to diagnose and treat the underlying cause.”

Mange 

An infestation of mites causes the skin condition known as mange. Mites are tiny parasites closely related to ticks that burrow into the skin and cause intense itching (the dog’s response of scratching, licking, and biting results in hair loss) and, many times, owners may notice a rash on the dog’s belly, inner thighs, and groin. There are two types of mites that can cause mange, therefore there are two types of mange.  

Sarcoptic mange is caused by a type of mite that is highly contagious to other animals and to humans, where the condition is known as scabies.

Demodex mites cause demodectic mange. The demodex mite—which is specific to its host: dogs, cats, humans, and is not contagious—lives in small numbers on the skin of healthy dogs without causing a problem. The mites cause mange when their population explodes because a dog’s immune system is functioning below a healthy capacity. Dogs with demodectic mange have an underlying condition that is compromising their immune systems.  

Pyoderma 

Pyoderma, a Greek word that translates to pus in the skin, is a common condition caused by a bacterial infection. You may notice pimples on your dog’s skin, dry, crusty, scaly skin, and hair loss. You may also see a rash on your dog’s belly. In many cases this infection is secondary to a condition such as allergies or parasites like fleas. In otherwise healthy animals, Pyoderma is resolved with antibiotics.

Folliculitis 

Folliculitis is a term that translates to inflammation of hair follicles, usually caused by a bacterial infection. When your dog has folliculitis, you may see swelling, redness, and pimples on the skin, itching, hair loss. Many times, the bacterial infection that results in folliculitis actually stems from a systemic problem such as atopic dermatitis (allergies) or an endocrine disorder. Treatment can include topical (applied to the skin) and systemic (oral or injected) antibiotics as well as treatment of the underlying condition that is contributing to the infection. 

Seborrhea 

In humans, this condition is commonly known as dandruff or cradle cap. In dogs, the oily, flaky skin known as seborrhea or seborrheic dermatitis, is a common skin disorder caused by overactive sebaceous glands in the skin, usually on the dog’s back. You may notice flaking (dandruff) on the dog’s fur and bedding. You may also notice a pungent doggy smell caused by the excess sebum. This condition, too, is often linked to underlying medical problems, and treatment involves identifying and treating the root issue. Managing seborrhea can include changes to the diet or the introduction of supplements, special shampoos and sprays, or steroids. 

Underlying Issues

In many cases, skin conditions in dogs are symptoms or secondary infections of a serious systemic issue—"atopic dermatitis [systemic allergies], endocrine disorders, and autoimmune disorders can all lead to chronic skin disease,” Conover says. “Chronic ear infections and chronic itching and skin irritation are two of the red flags that a dog may have an underlying issue.”

For this reason, it is imperative you contact your veterinarian when you notice your dog has irritated, itchy skin. While your dog may just need a round of antibiotics, it is possible he may be battling a much more serious disease, some of which are incurable. “In that case, we focus on symptom management and quality of life for both the dog and the owner. In recent years, new treatment options have been developed to help us better manage these cases.”