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Symptoms of skin allergies in cats

With cats it can sometimes be difficult to tell the difference between skin disease caused by allergies and skin disease due to other causes. Many cats will not typically scratch like dogs, and will tend to excessively groom themselves instead. Some cats may even be “secret groomers” leaving us humans unaware of their behaviours.

Common symptoms of skin disease or itchiness (pruritus) in cats include:

• Obvious scratching, itching and self-induced skin trauma.
• Symmetrical hair loss, often on the flanks or underbelly.
• “Miliary dermatitis”. This is characterised by tiny little crusts and sores over the body.
• Eosinophilic granuloma complex. This includes a number of types of lesions including indolent ulcers, eosinophilic plaques and eosinophilic granulomas.
• Some cats will have more than one symptom

Causes

Common causes of skin disease in cats include:

• Flea bites and flea allergies
• Food hypersensitivity/food allergy
• Atopy: Allergy towards pollens, grasses, house dust mite, mould. Absorbed through the skin or inhaled. Similar to human hay fever.
• Insect bites (mosquitoes, bees, wasps)
• Mites: Ear mites (Otodectes cynotis), follicular mites
• Skin infections (bacterial, yeast, dermatophytes/ringworm, viral)
• Feline acne
• Auto-immune skin disease (Pemphegus foliaceous)
• Neoplasia (skin cancer)
• Psychogenic alopecia

Complications

Itchy skin can sometimes result in severe self-mutilation where the damaged skin becomes infected with bacteria and/or yeast. Long standing, untreated cases can develop severe skin infections. Cats with severe skin irritation may go off their food or become short tempered.

Diagnostic Approach

Pruritic skin disease can be one of the most frustrating conditions to diagnose and treat successfully. A successful outcome will depend on the correct communication between you and your veterinarian alongside regular monitoring of the condition. A logical, standardized approach to all cases is necessary for a good response to treatment.

The first step is the recording of a complete and detailed history. It is important that you try and give as much information to your vet as possible. Some things your vet will need to know include:

What do you feed your cat? Do they eat any other pet’s food?
What flea control do you use and how often?
Do you have any other pets?
Does your cat have free access outdoors?
How long has the condition been going for?
Any previous medications that have been used?

Next, a full clinical examination will be performed to look at the skin lesions. Other parts of the body and other organs will be examined to make sure there isn’t an underlying problem present. This can be very difficult to determine at the time of presentation as allergies may often disguise other conditions. Sometimes underlying problems can only be fully investigated once the allergy has been attended to.

Thirdly, comes the diagnostic investigation and this will likely include a number of skin tests such as skin scrapings, surface cytology, hair pluck examination and fungal cultures. For cats over seven years of age, it is also recommended to perform laboratory testing to include a complete blood count, chemistry panel, thyroid hormone testing and urinalysis. All these test can be run at our hospital meaning you get your cat’s results quickly.

The last part of the diagnosis involves assessing your cat’s response to treatment. In some cases that do not respond appropriately, further tests may be necessary such as intradermal skin testing or Allercept blood testing. For these procedures we have a specialist veterinary dermatologist that conducts appointments by referral from our hospital.

Treatment of skin allergies

This is often a stepped and logical approach:

• Fleas

In all cases of skin allergies, an appropriate flea control program is essential. Bear in mind that it only takes one flea bite to trigger an allergic response in a susceptible cat. An absence of fleas on their coat does not rule out fleas either as most allergic cats will fastidiously groom the fleas off before the humans find them. Even if there are no fleas evident on your cat, flea control is a vital component of their treatment plan. Speak to one of our vets for the recommended flea treatment plan for your cat.

• Infection

Traumatized skin can become infected with bacteria and may even have a chronic yeast infection present.  This infection can cause the skin to become even itchier than it originally was. Antibiotics are generally dispensed for this. An anti-fungal or anti-bacterial shampoo can also be used.

• Food Elimination Trial

In cases where the cat has symptoms of allergies all year round with no seasonality, a hypoallergenic food trial will likely form part of both the diagnostic and treatment plan.

A gold standard elimination diet involves feeding a new and unique source of protein such as cooked kangaroo, rabbit or horse for a minimum of 8-10 weeks in order to rule out food as a potential cause or exacerbating factor.

Royal Canin Hypoallergenic and Hills Z/D are both commercially available veterinary prescription diets that are designed to be fed as an elimination diets and are both available in our practice. Most cats with food allergies do extremely well on these diets however there are a small percentage (approx 5%) of cats with food allergies that will still react to these diets.

It is important to introduce the new food very gradually to your cat over 1-2 weeks to increase palatability. The elimination diet does not commence until you have managed to get your cat on 100% of the special diet.

It is very important during the food trial that you feed your cat ONLY the suggested food. One small treat, one small left over from a meal, is all that is needed to negate the process. For more detailed information please read our information page on Food Elimination Diets in Cats. If your cat goes off their food, please call us as soon as possible.

• Drug Treatment

The most commonly used drugs to aid in the treatment and reduce clinical symptoms are cortisone and anti-histamines. Cortisone can be given in tablet or liquid form, or applied topically as a local spray or ointment. Anti-histamines can be very variable in their efficacy and it may be necessary to try various different types of anti-histamines, before finding one that works for your cat.

The latest research seems to show that anti-histamines together with omega 3 fatty acids (cold fish oils or evening primrose oil) act synergistically (i.e. enhance each other’s effects). So using them together may be of great benefit.

A newer drug called cyclosporine has been used with success in a number of refractory skin allergy cases.

• Local Skin Treatment

Reducing the “itch threshold” can be aided by the use of localized products on the skin. Cold water baths can be used to “cool” the skin in calm, easy to handle cats. As mentioned above, cortisone sprays (Cortavance) or ointments (Elocon) can also be applied directly onto the skin thus avoiding tablets and their side effects. 

• Desensitization

With specific cases that have undergone intra-dermal testing or Allercept blood testing with our specialist dermatologist, a tailor made vaccine can be developed. This is injected at regular intervals to try and “desensitize” your cat to various allergens. This is performed under the guidance of a specialist dermatologist.

• Other

Fatty acids (cold fish oil capsules) are often used in the treatment of allergic skin conditions and may go a long way toward reducing the necessity for certain drugs like cortisone.

Royal Canin Hypoallergenic and Royal Canin Sensitivity Control are prescription diets for cats with skin allergies, containing specific supplements known to improve the overall health of the skin, increase the skin’s natural defences and promote healing.

Royal Canin Obesity may be recommended for overweight cats that can be more susceptible to dermatitis.

What else can I do?

Other possible ways that you can aid in the prevention of allergen exposure at home include:

• Wash your cat’s bedding once weekly. In some cases it may even be best to change the bedding completely, foam bedding is best for allergic cases.
• Avoid pollen allergens, keep your cat inside on high pollen count days, especially if windy. Most plants pollinate between 5am and 10am in the morning.
• Maintain stringent long-term flea control regardless of whether you see a flea or not
• Regular check-ups are necessary, especially in the first 3-6 months of treatment. It is during these check-ups that your vet will make adjustments to treatment and monitor progress and eventually institute a long-term plan.
• Attend to any flare-ups quickly before secondary problems set in, otherwise it is likely to result in a need to start all over again with the treatment etc.
• Understand that communication with your vet is paramount to a successful outcome. All these cases require some form of long-term and often life-long, treatment in order to achieve control of their condition.

Disclaimer: Please note that the information provided on this page does not replace the advice of your veterinarian. If you are concerned about your cat’s health in any way, we strongly recommend you seek veterinary advice.