How to treat pet dermatitis
Atopy or Atopic Dermatitis is one of the most common forms of allergic skin disease in dogs. Like human allergies, it is brought on by seasonal pollen and other airborne allergens.
While humans tend to get hay fever, dogs tend to present with itchy skin or ear problems.
Affected animals persistently scratch, lick and bite to get relief. Constant scratching can lead to sores, hair loss and secondary infections.
Cats can suffer from allergic dermatitis, too, often hiding to constantly scratch and groom. Respiratory symptoms (runny nose, watery eyes or coughing, sneezing and wheezing) may also be seen in cats.
Management of the disease can be difficult and usually requires lifelong therapy.
What is atopy?
Atopic or allergic dermatitis is caused by sensitivity to allergens in the environment, such as dust mites, mould spores or tree, grass and weed pollens. Diet can also affect the condition. In the allergic state, the animals’s immune system ‘overreacts’ to foreign substances (allergens) to which it is exposed, resulting in itchiness, either localized (in one or several areas) or generalized (all over the dog).
Many of these allergies occur seasonally, just as in humans, and get worse each year with additional allergen exposure, so early treatment is vital. It is thought to be a genetically inherited disease seen in all breeds of dogs, although Bull Terriers, Boxers, Dalmatians, Retrievers and West Highland Terriers seem to be at higher risk.
What are the signs of atopy?
Atopy is most commonly seen for the first time in dogs 6 months to 3 years of age, and initially may be associated with the ‘pollen’ season, although symptoms are constantly present in older dogs.
Inflammation of the skin produces severe itching, usually generalized. The dog chews, licks, and scratches its skin, resulting in hair loss and secondary infections. The problem may be worse in the axillae (armpits) and underside of the abdomen. Some dogs mainly chew their feet. Saliva will stain light coloured hair, so dogs that lick excessively will have reddish brown areas on their coat.
Rubbing of the face is also a common sign, as is inflamed ears and recurrent ear infections.
Seborrhoea is the overproduction of sebum by inflamed skin. It gives the coat an oily feel and a musty, strong smell. Bacteria thrive in sebum and this also contributes to the odour.
In cats, you may see red, bumpy skin, hair loss, inflammation, skin tearing on the head and neck, and sometimes respiratory symptoms like a runny nose, sneezing or wheezing.
How is atopy diagnosed?
Diagnosing atopic dermatitis is based on exclusion of other disorder with similar signs, such as Flea allergy dermatitis (FAD), Scabies (caused by burrowing mites), food allergy or bacterial and fungal skin infections.
Blood tests can be taken to confirm allergic dermatitis and indicate which allergens are causing the problem. A more reliable method is skin testing. Small amounts of the allergen are injected into the skin to see if an allergic reaction occurs at the site. A skin specialist usually performs this procedure.
How is atopy treated?
There is no cure for atopic dermatitis, but there are many treatment options. Avoidance of the offending allergen is the most effective form of control of the disease but this is often impossible.
Treatment may include a combination of:
- Anti-inflammatory drugs (cortisone) – good for fast relief but side-effects may occur with high doses or long-term use
- Antihistamines – can help control itching, especially in conjunction with other treatments
- Antibiotics or antifungals for secondary skin infections
- Topical treatments – shampoos, rinses and anti-itch solutions offer immediate, short-term relief.
- Hyposensitisation – injections of increasingly large doses of allergens identified during a skin test to build resistance. Injections are usually given at home, and the animal may take up to 9 months to respond. This therapy may prevent flare recurrence, but often needs to be administered for life.
- Flea prevention – it is also very important for any pet with atopy to be on a year-round, comprehensive flea control program as they tend to be more sensitive to the bites of fleas as well.
- Food supplements – essential fatty acids have been found to help reduce itching in some dogs
- Immunomodulation – a specifically developed medication for dogs and cats is available from veterinarians. It targets the immune cells involved in the allergic reaction, providing long-term control of the allergic response in the animal’s skin. This medication has been proven in extensive trials to be very effective and well tolerated. It may also reduce the need for add-on medications. This treatment may be given lifelong if necessary.
Long-term management
The most important contributor to successful long-term management is following your veterinarian’s advice, and ensuring medication is always given on time. It can be tempting to stop treatment when symptoms improve but, without treatment, symptoms will almost certainly recur and that will mean a return to the misery of atopic dermatitis.
It can be difficult to avoid pollens but if your pet is allergic to house dust mites you can wash your pet’s bedding regularly, wash soft furnishings regularly, vacuum frequently with a high efficiency particle air (HEPA) filter cleaner, use air dehydration and purification systems, and use insecticides effective against house dust mites.
It’s important to take your pet to the vet as soon as it starts showing symptoms of constant scratching or grooming, rubbing the face and ears or chewing feet before the condition becomes harder to manage, nasty infections set in and your pet becomes just plain miserable.
By Provet Resident Vet
Contributors: Dr Rebecca Bragg BVSc, Dr Julia Adams BVSc
Last updated on 20 December 2019