- A variety of skin problems can affect dogs and cats, including allergies, bacterial and fungal infections, and parasite infestations.
- The signs of skin problems in pets can be very similar, so it is important to have your veterinarian examine your pet to determine the cause of the problem.
- Most skin problems in pets are curable or manageable. If your pet seems itchy or has skin that doesn’t look healthy, contact your veterinarian.
A wide variety of skin and coat conditions can cause your pet to itch and scratch, but pinpointing the problem can sometimes be difficult because many skin disorders have similar outward signs. Below are four major categories of skin conditions seen in cats and dogs.
Allergic Skin Diseases
Allergic skin disease develops when your pet’s immune system overreacts to certain substances (allergens), causing clinical signs that affect the skin. Your pet may come into contact with these allergens in several ways:
- Breathing. When allergens are inhaled, the associated skin disease is called atopy or atopic skin disease. Inhaled allergens can be molds, dust, plant pollens, or a variety of other agents.
- Touch. Sometimes, your pet can be allergic to things that make contact with the skin, such as grass or natural or artificial fibers. Pets that are allergic to components of flea saliva can develop flea allergic dermatitis if they are bitten by fleas.
- Eating. Some cases of allergic skin disease in pets are triggered by an allergy to something in the pet’s food.
Allergic skin disease causes itching, and pets that scratch excessively can damage their skin. Sometimes, frequent chewing, scratching, and biting can cause secondary skin infections, wounds, scabs, hair loss, and other problems.
Diagnosing allergic skin disease can be challenging because different types of allergies can have the same clinical signs, and allergic skin disease can look like many other types of skin problems. Your veterinarian will try to rule out other types of skin irritation before making a diagnosis of allergic skin disease.
Ideally, treatment of allergic skin disease involves reducing or eliminating your pet’s exposure to the allergens that are causing the problem. For example, if a pet has a food allergy, a special diet may be prescribed. If your pet is allergic to fleas, safe and effective flea control is essential to controlling the problem. For pets that are allergic to inhaled allergens, limiting their exposure (to grass or house dust, for example) is helpful, but medications are often necessary. In some cases, allergy testing may be recommended. If the exact allergens can be identified, a serum can be developed that, when administered to the pet in injections, reduces the pet’s sensitivity to the allergens over time.
Sometimes, the cause of an allergic skin problem can’t be determined right away. Fortunately, your veterinarian can frequently use medication to treat the itching without finding out exactly what the pet is allergic to. Although this is not a “cure,” the pet can be made more comfortable until a more permanent solution is possible. In general, the best remedy is to avoid whatever it is that sparks the allergic reaction.
Bacterial Skin Infections
All people (and pets) have bacteria on their skin. In most cases, these bacteria don’t cause a problem. However, when the skin is damaged (such as through scratching due to a skin allergy), a secondary bacterial infection can develop.
Bacterial skin infections, called pyoderma, are not contagious to people or other pets. However, the skin problems they cause, including pustules, open wounds, and infections that damage the hair follicles (leading to hair loss), can become a serious medical issue for affected pets.
Bacterial skin infections are usually diagnosed based on the patient’s medical history and the location and appearance of the affected area. Your veterinarian may also perform blood tests, skin tests, or bacterial culture testing to determine the exact origin of the problem. Many bacterial skin infections have an underlying cause, such as a parasite infestation, hormonal or immune system disorder, or allergy. If the underlying cause is not treated appropriately, the skin infection will likely return. In addition to treatment for the underlying cause, your veterinarian may recommend antibiotics, which can be administered in many forms, including pills, injections, shampoos, gels, ointments, and sprays.
Fungal Skin Infections
Malassezia. The most common fungal organism that causes skin problems in pets is a yeast called Malassezia. This infection generally occurs secondary to another skin problem, such as allergic skin disease or a bacterial skin infection. Fortunately, Malassezia is treatable through a variety of methods (including shampoos, gels/ointments, and pills). The key to resolving the problem for good is to successfully manage the underlying condition.
Ringworm. When most people hear ringworm, they may think of a parasite, but ringworm is actually a relatively common fungal skin infection. Ringworm causes crusty skin lesions and hair loss. It can occur anywhere on the body but commonly affects the head and legs. Sometimes the area of hair loss is circular, but not always. Diagnosis is best made via a fungal culture. For this test, your veterinarian will pluck a few hairs from an affected area and place the sample in a special solution to see if the ringworm organism will grow. Ringworm is treatable, usually through medicated baths, ointments/gels, or pills. Complete eradication of the infection can take a month or longer.
Ringworm can be quite contagious to people and other pets. Therefore, children and other household pets should be kept away from an infected pet during the treatment period. People who come into contact with the affected pet should wash their hands regularly.
Parasitic Skin Diseases
A number of parasites can infest dogs and cats. They can cause itching, which may lead to self-mutilation from excessive scratching and biting and other trauma to the skin. Fleas are one of the biggest culprits. Pet that are allergic to fleas may scratch excessively, causing redness, wounds, pustules, scabs, and hair loss in the affected areas. Even pets that aren’t allergic to fleas still experience itching and general misery from these parasites. Other small parasites, such as ticks, chiggers, lice, and biting flies, can also bother pets. For most of these parasites, your veterinarian can recommend a product to control them and protect your pet from their effects.
Mites that can affect dogs and cats include ear mites (which are contagious among pets and cause severe itching and ear infections); sarcoptic mites, which burrow under the skin, causing intense itching and skin lesions (known as scabies or red mange), and are contagious to people in the household; and Demodex mites, which are more common in dogs than in cats and are associated with itching, hair loss, and skin problems.
Most parasitic skin diseases can be diagnosed through direct visualization of the parasite (such as fleas), or by examining small samples of skin or debris under a microscope to diagnose the problem (such as ear or Demodex mites). All of these parasitic conditions are treatable, so if your pet is itching, or you notice any bald areas or skin wounds, contact your veterinarian.
Help Is Available
The skin problems listed here are the most common ones that affect dogs and cats, but there are many others, including immune-mediated skin disease, cancer involving the skin, and endocrine (hormonal) problems that affect the skin.
Most skin conditions can be cured or at least (as with some allergies) managed. No matter the cause of your pet’s skin problem, it is possible to ease his or her suffering. When you do, it will be a relief for both of you.