Feline atopic dermatitis, or feline atopy, is a type 1 allergy or hypersensitivity in which there is an exaggerated reaction by the body to an environmental allergen such as dust, mites or the pollen. It does not occur in all cats and there are no breeds more predisposed than others. The main clinical sign is itching associated with erythema, alopecia and other skin lesions. The process is usually worsened and fed back due to the constant scratching and licking of cats with this problem, predisposing them to secondary infections. Treatment is based on the use of immunosuppressive and anti-inflammatory therapy generally associated with essential fatty acids and the diagnosis is by exclusion.
What is the atopic dermatitis?
Atopic dermatitis is a common cutaneous pathology in cats that causes itching. Atopic dermatitis is an allergic reaction or type 1 hypersensitivity to environmental allergens such as pollen or dust mites, among others.
In this other article we mention the most common skin diseases in cats, among which is the one we are now addressing.
Pathogenesis of atopic dermatitis in cats
While in dogs it has been shown that atopic dermatitis has a genetic reason, in cats this does not occur, being the unknown cause, nor does it have a racial predisposition as it does in the canine species.
The pathogenesis of atopic dermatitis is complex and new concepts continue to be studied and discovered. As in humans, atopic dermatitis is thought to be associated with high activation of T-lymphocytes, poor cellular immunity, hyperstimulating Langerhans cells, and low IgE production on antibody-producing B cells. The dermatitis itself is contributed by an abnormal biochemical response and secretion of mediators by monocytes, mast cells, and eosinophils. In the case of cats, it is predictable that the inflammation at the skin level will continue to be self-perpetuating by the continuous scratching or licking of the cat, even when it is no longer exposed to the allergen that triggers the allergy.
Symptoms of atopic dermatitis in cats
There are several clinical signs that can suggest that it is a case of feline atopic dermatitis, but none is pathognomonic or diagnostic in itself. Symptoms usually appear between the first and third year of life, although it has also been observed in animals as young as 4 months or over 15 years old. Dermatitis can be seasonal, frequently associated with pollen, or non-seasonal, generally associated with allergens that remain throughout the year such as dust and its mites.
Clinical signs
Among the most frequent clinical signs we find pruritus or itching of different degrees of intensity between individuals, as well as dermatological signs such as: erythema or redness; hyperpigmentation or lichenification, that is, thickening of the skin at the interdigital level or on the concave face of the auricle and vertical canal, on the abdomen, periocular area, on the lips and in the armpits. It is also common for these areas to present alopecia depending on the degree of inflammation and the duration.
Secondary infections
Secondary infection by bacteria such as Staphylococcus or fungi such as Malassezia pachydermatis is common in these areas. Staphylococcus infection produces a superficial pyoderma that commonly presents erythematous papules that can form pustules or crusts and circular alopecic areas with scaly edges, known as "epidermal collares".
Another sign that is also common in atopic dermatitis in cats is otitis externa ceruminosa Generally, it occurs due to prolonged erythema which can produce hyperplasia of the tissues inside the auricle and ear canal, which predisposes to increased secretion of the glands whose secretion works as a culture medium for yeasts and bacteria that cause otitis.
Other signs that atopic dermatitis can cause in cats are:
- Feline eosinophilic granuloma complex lesions.
- Miliary dermatitis.
- Allergic asthma.
Diagnosis of atopic dermatitis in cats
Feline atopic dermatitis should be a diagnosis of exclusion that is only diagnosed when clinical signs are compatible and other causes have been ruled out of itching and similar symptoms included in its differential diagnosis, these are:
- Flea bite allergy dermatitis (DAAP)
- Superficial pyoderma
- External parasites
- Food hypersensitivity
- Dietary intolerance
- Malassezia pachydermatis dermatitis
- Contact dermatitis
allergy tests are performed when the diagnosis of atopic dermatitis has already been established, or is very likely, to identify the allergen or allergens responsible for the hypersensitivity picture and thus carry out an allergen-specific immunotherapy. These tests are based on allergen-specific IgE serology to measure the reactivity of blood antibodies against the allergen or intradermal tests by introducing the allergen directly into the cat's skin and observing the reaction.
To avoid inaccurate results with these tests, corticosteroids such as prednisolone should be withdrawn for three weeks before the test and antihistamines for 7 to 10 days before the test. To control the cat's itching during this time until testing, 1% hydrocortisone lotions or sprays can be applied to the affected areas twice daily, as long as that area is not going to be tested.
How to cure atopic dermatitis in cats? - Treatment
The treatment of feline atopic dermatitis is based on the use of various drugs and products to control and prevent the symptoms In general, combination therapy with glucocorticoids, immunotherapy, cyclosporine, antihistamines, or essential fatty acids is used.
Glucocorticoids
These drugs are the mainstay of treatment for atopic dermatitis in cats to control itching and inflammation Prednisolone is often used at dose of 1-2 mg/kg daily for 7-10 days to reduce to the lowest possible dose that controls clinical signs. Methylprednisolone can also be used at a dose of 0.8 mg/kg every 24 hours and should be reduced in the same way to the lowest effective dose.
Allergen-specific immunotherapy
Consists of the progressive administration of greater quantities of the allergen with subcutaneous injection to reduce or eliminate the clinical signs of upcoming natural exposures. This treatment should be carried out for at least 9-12 months. In most cats there is a 50% reduction in these signs. However, they usually need some coadjuvant treatment of the ones we are commenting on to completely control the symptoms.
Cyclosporin
The drug cyclosporine is authorized for use in feline atopic dermatitis at a dose of 7.5 mg/kg orally every day. However, this drug causes immunosuppression and can cause secondary infections or reactivation of toxoplasmosis or herpesvirus, especially if combined with glucocorticoids.
Antihistamines
Not authorized for use in cats, but may be useful in reducing symptoms in 40-70% of cases, alone or in combination with glucocorticoids and essential fatty acids. The most frequently used are chlorphenamine and cetirizine
Essential fatty acids
They help to control itching in 20-50% of cats, but their effect can take up to 3 months. Better results are obtained if they are combined with glucocorticoids and antihistamines.
Discover in this other article Foods rich in omega 3 for cats.
Home remedies for atopic dermatitis in cats
Refreshing the most itchy areas, use of aloe vera on the inflamed areas(making sure the cat doesn't ingest it) or baths with hypoallergenic, soothing or moisturizing shampoos can help calm your cat's itchiness somewhat, but you cannot pretend to treat feline atopic dermatitis with home remedies. So if you see that your cat scratches a lot, has red areas, no hair, looks bad and is more nervous because of this itching, you should go to a veterinary center so that they can prescribe the best treatment for your cat.
