Diagnosing Odor in Cats

Skin odor is a common manifestation of a skin infection. The most common skin infections in cats are bacterial (superficial pyoderma) and yeast (Malassezia dermatitis) infections. Skin discharge and/or odor can indicate that your cat may be suffering from a skin infection.

What are bacterial and yeast infections?

Bacterial infections are usually caused by bacteria that are part of the normal flora of the skin (e.g. Staphylococcus intermedius). For this reason, the infection is not contagious to other animals. In cats that have abnormal skin (e.g. allergies) the bacteria increases in number and causes red bumps (papules) and rancid odor. Some cats with bacterial skin infections also develop excessive shedding, patchy hair loss, and scaling. If the infection is left untreated, it may reach deeper parts of the skin. In these cases, nodules that have a purulent (pus) discharge develop. In most cases skin infections are secondary, so it is very important to pursue an underlying cause. Failure to do so will result in reoccurring infections.

Animals often develop a yeast infection (Malassezia dermatitis), which manifests itself as greasy, red, itchy skin with a rancid odor. Areas most commonly affected include the ventral neck, groin, armpits (axillae), and perineal areas. This infection is also secondary to an underlying disease, most commonly allergies. In some cats this may be a consequence of chronic antibiotic and steroid therapy but, as a general rule, cats do not develop yeast infections after antibiotic therapy as commonly as people do.

Diagnosis of Skin Discharge or Odor in Cats

• History is very important for the proper diagnosis of skin diseases. Your veterinarian will ask questions regarding the age of onset, progression of the disease, and response to previous treatments.

• Skin cytology provides useful information on the type and severity of infection. Your veterinarian may take samples of skin (e.g. swabs or tape impressions).

• In some cases, a biopsy may be necessary to establish a final diagnosis. Some samples may be used for cultures of various types while others may be sent to a pathologist to obtain more information about the cells that are present in the skin.

Treatment for Bacterial Dermatitis

Treatment for bacterial skin disorders is antibiotics. Some of the more commonly used antibiotics include ampicillin, cephalexin, enrofloxacin, clindamycin, clavulinc acid and sulf based drugs.

The minimum length of therapy for superficial pyoderma is 3 to 4 weeks. The minimum length of therapy for deep pyoderma is 8 weeks. As a rule, therapy should be continued for 2 to 4 weeks beyond the resolution of clinical signs.

Treatment of Malassezia Dermatitis​

Systemic therapy is reserved for severe cases. It is important to note that griseofulvin is not effective against yeasts. Ketoconazole, itraconazole and fluconazole are all effective against Malassezia.

Topical therapy as the sole treatment is only effective in mild cases while severe cases usually require systemic therapy. Selenium sulfide (Selsun Blue®) is a keratolytic, anti-seborrheic, degreasing agent that will kill Malassezia (effective in 65 percent of cases).

Ketoconazole shampoo (Nizoral®) is approved in many countries for the treatment of seborrheic dermatitis in people and is usually effective in killing Malassezia.

Chlorexidine at 2 to 4 percent might be effective against yeasts, 0.5 to 1 percent is not effective.

Miconazole (Dermazole ®, Resi-zole® leave on conditioner) is also effective.

Vinegar/water rinse (1/5 to 1/10) is a cheap and effective long-term maintenance treatment to prevent relapses.

At-Home Care for Cats

You will need to shampoo your cat with medicated shampoos. Benzoyl Peroxide is an excellent antibacterial antibiotic (e.g. Oxydex®, Pyoben® shampoo). Other antifungal shampoos contain miconazole or ketoconazole (e.g. Nizoral® shampoo for dandruff is now available OTC).

Contact time is important when using a medicated shampoo. You should allow a 10 to 15 minutes contact time for the product to be effective. Leave-on products are also available on the market for prolonged efficacy.

You may have to administer oral medications (either antibiotics or antifungal medications) to help treat the infection. Compliance is very important. Some cats may require medications for a prolonged time as skin infections usually take a while to clear. Speak with your veterinarian before administering medication to your pet.

If your cat keeps relapsing with infections, it is important to pursue an underlying cause. This will decrease the frequency of relapses and reduce the risk of resistance to medications used for prolonged periods of time.

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Types of Skin Problems Found in Cats

If your cat's got a case of constant scratching and licking, a skin problem may be to blame. Cats are susceptible to skin infections, parasites, allergies, and many other conditions commonly seen in people.

Feline Acne

Yes—cats get pimples, too. Feline acne typically appears on and around a cat's chin. Possible causes include stress, poor grooming, a reaction to a medication, an underlying skin condition, or even the plastic bowl you put out with her food or water. Your veterinarian may recommend a specialized shampoo or gel to clear up the breakout, or antibiotics if a bacterial infection accompanies the acne.

Bacterial Infections

In many cases, bacterial skin infections develop as a result of another skin problem. For example, feline acne can make a cat's hair follicles more vulnerable to infection, resulting in folliculitis. Bacterial infections may be treated with antibiotics, but it's important to address any underlying skin conditions to prevent a recurrence.

Yeast Infections

Yeast infections are caused by a fungus and are also more likely in cats that have other medical problems. The ear is one of the most common spots for a yeast infection. Symptoms may include a black or yellow discharge, redness of the ear flap, and persistent scratching of the ear. Yeast infections respond well to treatment with antifungal medicine, but be sure to get a diagnosis from a veterinarian before using anything on your cat.

Ringworm

Ringworm is another type of fungus that affects cats, especially if they are under age 1. It may cause circular lesions on a cat’s head, ears, and forelimbs as well as any other part of the body. The skin around these lesions is often flaky and bald. Ringworm is highly contagious and can spread to other pets in the home, as well as to people. Treatment depends on the severity but may include specialized shampoos, ointments, or oral medications.

Sporotrichosis

Yet another fungus — although rare — sporotrichosis produces small, hard skin lesions that may leak fluid. Sporotrichosis is considered to be a public health concern because the fungus is known to spread from cats to humans. People with a compromised immune system are especially vulnerable. For these reasons, cats with sporotrichosis should be treated promptly, and caregivers should be meticulous about hygiene.

Allergic Dermatitis

Cats can have allergic reactions to grooming products, food, and environmental irritants, such as pollen or flea bites. Scratching the head or neck is a common sign of food allergies. Symptoms of other allergies include chewing on the paws or base of the tail or scratching the ears. Allergies can also cause hair loss or skin lesions anywhere on the body, including the belly. There are a variety of treatments to soothe itchy skin associated with allergies, but avoiding exposure to the irritants is the best strategy.

Shedding and Hair Loss (Alopecia)

If you live with cats, you learn to cope with cat hair on your favorite sweater. But if you notice your cat is losing more hair than usual or has bald patches, see your veterinarian as soon as possible. Abnormal hair loss can be a warning sign of several illnesses, as well as fleas, stress, allergies, or poor nutrition.

Fleas

The idea of tiny insects feeding on the blood of your cat may make you shudder, but fleas are a very common problem. You can look for them or their droppings in a cat's coat, especially where the fur is pale. Other signs of a flea infestation are persistent scratching, crusty skin lesions, and thinning hair above the base of the tail. To eradicate fleas, you’ll need to treat your cat as well as your furniture, bedding, and rugs.

What has been the gold standard of flea control is a monthly flea prevention protocol. It not only kills fleas on your cat, but those in your home should eventually be eliminated as they fail to reproduce. Monthly control, though, is not the only option. There are also products that can be given every other month as well as a collar that can provide protection for up to 8 months. Talk to your vet about what would be best for your cat. And remember: Treating all pets in the home is necessary for whatever plan you use to be effective.

Ear Mites

Ear mites are tiny parasites that are drawn to the wax and oils inside a cat’s ear. As they feed, they cause inflammation that can lead to a serious skin or ear infection. Signs of ear mites include excessive scratching of the ears, head shaking, and a strong odor and a dark discharge from the ears. Suspect ear mites when both ears are affected. Mites can be treated with a topical product prescribed by your vet. Ear mites are also contagious to other animals.

Lice

Lice are parasites that feed on dry skin. They are commonly found on young, neglected cats and often go unnoticed. Large infestations can lead to scratching, restlessness, unusual coat appearance, and hair loss. Like mites, lice can be treated with a topical solution. Because lice are species-specific, you do not need to worry about getting lice from your cat.

Stud Tail

Also called tail gland hyperplasia, stud tail refers to overactive glands on the top of the tail. These glands produce waxy excretions that result in hair loss and crusty lesions. In severe cases, the condition can make the tail vulnerable to bacterial infections. Neutering may eliminate the problem in male cats. Other treatment options include diligent grooming of the tail and the use of specially formulated shampoos.

Eosinophilic Granuloma

If your cat has raised ulcers or lesions on the nose or lips, she may be having a type of allergic reaction known as an eosinophilic granuloma. This reaction can occur anywhere on the body, but is most common on the face, pads of the feet, and thighs. Food allergies or fleas are sometimes to blame, but the lesions can also result from bacterial infections. Treatment depends on what is causing the reaction.

Skin Tumors

A lump in your cat's skin is not necessarily cancer, but should be checked by a veterinarian. Older cats and those with white ears and heads are especially susceptible to skin cancer. To confirm a diagnosis of cancer, a biopsy is necessary. If the lump is small enough, a vet may recommend removing it entirely. For tumors that have not spread, this may be the only treatment needed.

Dry, Flaky Skin

Like people, some cats get dry, flaky skin in the winter. It's usually nothing serious, but have your veterinarian take a look. Persistent dandruff may be a sign of poor nutrition, inadequate grooming, or an underlying medical problem. Special shampoos and supplements of omega-3 fatty acids can help treat feline dandruff.

Compulsive Grooming

Cats are known to be fastidious groomers, but sometimes they overdo it. Compulsive licking, chewing, or sucking on the skin may lead to irritation, infection, and thinning hair (a condition called psychogenic alopecia). Cats may groom compulsively in response to stress, such as moving into a new home, but they may also overgroom due to a medical problem such as arthritis. If this describes your cat, talk to your vet about stress reduction and behavior modification strategies that can help as well as address some underlying medical issues.

When to See the Vet

Check with your veterinarian as soon as possible if you find any oddities on your cat’s skin -- flaking, scaling, redness, or bald patches. Even if the skin looks fine, your cat should be examined if she is scratching, licking, or biting herself excessively.

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