Overview
Atopic dermatitis is called CAD for short. The main symptom of CAD is itching, manifested as excessive scratching, rubbing, biting and Self-licking and other behaviors.
Cause
The incidence of atopic dermatitis varies and in some studies has been reported to be as high as 73% of all allergic cats, or second only to flea allergy. There may be a genetic predisposition here, as some Families have a higher incidence, but no specific gene has been identified. In cats with both seasonal and non-seasonal allergies, a study of 66 cats with atopic dermatitis found that: 50% had fleas, 58% were non-seasonal, 39% were both seasonal and non-seasonal, and 5% were allergic to pollen only , dust mites in the home are the most common non-seasonal response.
Main symptoms
Pruritic papular crusting (milial dermatitis), alopecia —barber alopecia from autoinjury (symmetrical alopecia in cats), erosive-exfoliative dermatitis from autoinjury, eosinophilic Granulomatous compound lesions, asthma, combined symptoms. Indistinguishable from other allergic symptoms, although there may be seasonality, many cases have flea allergy, some food allergy, in cats, respiratory symptoms are more common.
Diagnostic criteria
Intradermal antigen testing is more difficult to do than in dogs and more difficult to interpret, in vitro testing is helpful.
Treatment methods
Glucocorticoids are the most commonly used drugs to control AD itching. Cautious dosing and short-term administration can also cause mild side effects in animals. Many dermatologists often choose this drug when other treatments have not worked. The specific recommended medications are: prednisone, prednisolone and methylprednisolone, 0.5-1mg/kg/day, orally, for 5-7 consecutive days. Since glucocorticoids are the AD treatment drugs with the strongest side effects, they are not suitable for long-term use unless there is no other alternative. The antipruritic mechanism of these drugs is to inhibit phospholipase A2, which is the rate-limiting step in the synthesis of prostaglandins and leukotrienes, effectively blocking the entire inflammatory cascade and rapidly relieving itching. Side effects are equally famous.
Short-term use common: shortness of breath, polyuria, polydipsia and polyphagia, side effects vary greatly between individuals, making it difficult for veterinarians to predict. In some cases, iatrogenic Cushing’s syndrome occurred only because of the use of steroid-containing eye drops, while in some cases, multiple injections of long-acting steroids had no clinical side effects. In contrast, oral and injectable short-acting corticosteroids are routine options, and longer-acting injections are safer.
2. Antihistamines
Antihistamines are best used at the beginning of the itching season and are not effective for severe itching. Simultaneous use of antihistamines, essential fatty acids, and topical treatments can significantly control the degree of pruritus in some cases, thereby reducing the incidence of superficial pyoderma and other secondary diseases. The first-generation H1 blockers are representative of antihistamines. Due to their anticholinergic properties, they are prone to side effects of drowsiness or excitement. The antipruritic effect of this drug is unpredictable, but the risk is low, so it is suitable for use in most cases. It usually takes 14-21 days to see results. These drugs moderately regulate the synthesis of leukotrienes and prostaglandins (for which fatty acids and arachidonic acid are precursors) through competitive inhibition. The metabolites of essential fatty acids are less inflammatory substances. When high doses of ω-3 fatty acids are given, they can replace the enzymes that occupy the same position as arachidonic acid, and its anti-inflammatory mechanism comes from this. Therefore, taking essential fatty acids at the same time can reduce the dosage of steroids and antihistamines used to treat allergies. It was investigated that daily oral administration of fish oil containing EPA (66mg/kg) also has the above effects.
