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Flea allergy dermatitis (FAD) is an allergic response to flea bites that causes some cats to have extra extreme pores and skin issues than are normally seen with fleas. It happens when a cat is allergic to particular allergens in flea saliva.
For many cats, the presence of even a number of fleas will nonetheless result in solely delicate itching and scratching. In cats with FAD, nonetheless, the immune system identifies allergens in flea saliva as international and harmful to the physique, resulting in a extra extreme pores and skin response.
Learn on to be taught what flea allergy dermatitis is, how one can acknowledge it, widespread remedy choices, and how one can greatest forestall it.
Fast Overview: Flea Allergy Dermatitis in Cats
Causes of Flea Allergy Dermatitis

An allergic response to a flea’s saliva is at all times the reason for flea allergy dermatitis. KanphotoSS / Shutterstock.com
There is just one reason behind flea allergy dermatitis: an allergic response to a flea chew.
The severity of flea allergy dermatitis doesn’t rely upon the variety of fleas current. In concept, a single flea chew may trigger signs in cats with a major allergy. Actually, it is extremely widespread for only a few fleas to be current in cats after they arrive on the vet for an examination. The severity as an alternative relies upon solely on a person cat’s immune system and the way pronounced its response is.
Signs of Flea Allergy Dermatitis
There are three classes of signs that could be seen with flea allergy dermatitis.
Presence of Fleas
In some instances of FAD, reside fleas could also be seen on the cat’s pores and skin. Fleas are small however are seen to the bare eye.
Nonetheless, not with the ability to spot any of those creatures doesn’t rule out flea-allergic dermatitis. Once I see these sufferers, I’ve discovered it’s truly widespread to see few or no fleas in any respect. It is because a cat with FAD is usually extra proactive in eliminating seen fleas by grooming habits as a result of the bites are a lot extra irritating. Nonetheless, a single stray flea may induce FAD.
If no reside fleas are seen, there should be proof of their presence by flea filth. That is the time period for the feces that fleas depart behind on the pores and skin. After feeding or taking a blood meal from a cat’s pores and skin, fleas will defecate tiny specks of darkish black materials. Flea filth could also be down close to the pores and skin on the base of the fur and hidden from view by fluffy fur coats.
Pores and skin Look
There are particular dermatological indicators you might even see in a cat with FAD:
- Papules and crusts: One of many hallmarks of flea allergy dermatitis is the presence of small raised pink bumps, or papules, which might be typically just a little crusty in look. These are normally discovered across the head and neck in addition to close to the bottom of the tail. These bumps are usually not the precise bites themselves however the best way the allergy manifests on the pores and skin.
- Excoriations/Rashes: Pink, uncooked, ulcerated areas could also be current, particularly in cats which have been scratching lots. Cats’ sharp nails could cause important trauma to their very own pores and skin, resulting in irritation and reddened patches of pores and skin.
- Hair loss: Affected cats could groom and scratch to the purpose of dropping hair over drawback areas.
Conduct
The itching and scratching attributable to the sensitivity to flea bites and the ensuing irritation can result in behavioral adjustments. Cats could act erratically when bitten, racing off by the house after which licking or chewing excessively. Some cats overgroom (groom or chew at themselves extra typically or for longer spells) and might seem stressed and unable to settle.
Analysis of Flea Allergy Dermatitis

Hair loss, rash, or raised crusty bumps on the top, neck, or base of the tail are a typical sample with flea allergy dermatitis. Miroslav Pesek / Shutterstock.com
A veterinarian’s prognosis of FAD is predicated on three issues, alone or together.
Reside Fleas
Your vet could use a flea comb that has slim bristles to search for fleas and flea filth. In lots of instances, only a few fleas – and even none in any respect – are current. Nonetheless, the absence of fleas throughout an examination doesn’t rule out FAD. On this case, your vet could depend on the presence of attribute pores and skin lesions and/or allergen testing.
Pores and skin Lesions
The looks of crusty pink papules on the top, neck, and high of the again close to the tail could extremely recommend FAD as a trigger to a veterinarian.
I do know from private expertise that it might actually be troublesome for a vet to have the dialogue with a cat mum or dad that fleas are the probably trigger if that is the one signal. That is comprehensible, however it’s necessary to do not forget that cats can nonetheless have FAD even when they’re indoor solely, if fleas have by no means been seen within the dwelling, and even when fleas aren’t current on the cat throughout an examination.
Flea Allergy Testing
There are two methods for flea allergy testing to be carried out.
The primary is intradermal pores and skin testing. A small quantity of flea saliva allergen is injected below the pores and skin. The dimensions of the localized pores and skin swelling (referred to as a wheal) that outcomes is in comparison with a unfavourable management. If the scale of the flea saliva allergen website is 3-5mm bigger than the management, this helps FAD. This testing technique is most frequently supplied by veterinary dermatologists.
The second technique is with blood, or serological testing, which will be provided by normal practices like my very own. On this technique, blood serum is evaluated for antibodies, or immunoglobulins, to flea saliva allergens. The presence of immunoglobulin E (IgE) directed in opposition to flea saliva antigens could help an FAD prognosis.
Remedies for Flea Allergy Dermatitis
The essential parts of treating flea allergy dermatitis are to kill and remove the fleas, and to deal with the allergic response.
Flea Remedy
If fleas are visibly current, our first focus as vets is to kill the fleas and finish the infestation on the cat. This can be with an oral medicine like Capstar (nitenpyram) or a topical product like Frontline spray. There are many different merchandise for cats that proceed to deal with and forestall fleas. Some merchandise kill fleas sooner than others, and a few handle extra levels of the flea life cycle than others.
In cats that permit it, bathing could also be useful to take away lifeless fleas, flea filth, and to calm irritated pores and skin. Your vet could advocate a selected shampoo. Remember the fact that bathing a cat inside 24 hours of software of a topical flea product could lower effectiveness of the product.
The house surroundings should even be addressed. Flea eggs and pupae which might be current within the dwelling could hatch days or even weeks later. On the minimal, all bedding ought to be washed on a sizzling water cycle and the house ought to be completely vacuumed, together with between sofa cushions and below pillows.
There are dwelling remedy merchandise, like sprays, that can be utilized to deal with exhausting to succeed in areas like cracks in floorboards and below furnishings. These is probably not protected on or close to pets when sprayed, so comply with instructions rigorously. Skilled remedy could also be required in some instances the place a flea infestation is in depth.
In lots of instances, relying on what number of fleas are current within the dwelling surroundings and what number of eggs they’ve had a possibility to put (as much as 50 a day!), it might take wherever from 1-3 months to totally resolve a flea infestation within the dwelling.
Allergy Medicines
Addressing the allergic response could contain steroids and anti-histamine medicine. Normally, over-the-counter antihistamines is not going to be adequate on their very own and steroid medicine will likely be crucial. The most typical steroid medicines used are oral prednisolone and the injectable Depo-Medrol (methylprednisolone acetate).
Immunotherapy consists of utilizing small quantities of allergen to desensitize the physique and practice the immune system to not react to it. It is a widespread strategy to treating pets with a generalized environmental allergy dysfunction, or atopy. Immunotherapy for flea allergy particularly could also be included in immunotherapy, however has various outcomes [3].
Antibiotics
If a cat scratched themselves, resulting in open wounds, secondary bacterial an infection is a chance. Your veterinarian will assess the pores and skin to see if treating for bacterial an infection is important with an acceptable antibiotic.
Prevention of Flea Allergy Dermatitis

The right place to use a flea remedy medicine is on the base of the neck simply in entrance of the shoulders. Nick Alias / Shutterstock.com
The one solution to forestall flea allergy dermatitis is to forestall any flea bites from occurring.
Common use of flea prevention for cats is probably the most dependable method to make sure that fleas are faraway from the house surroundings. If all pets in a house are handled, fleas can’t reproduce and an infestation can’t happen.
I’ve discovered it might be very tough to manage this dysfunction for cats who go outside as a result of most merchandise require a flea to come back in touch with them. Repelling fleas and rapid-action merchandise are suggested, and environmental remedies across the dwelling could assist.
Cat Care Suggestions
- Deal with all pets: In case you have a cat with FAD, hold all pets within the dwelling rigorously handled with preventative flea medicine to maintain the house as flea-free as doable
- Deal with the surroundings: Most flea merchandise for cats don’t repel fleas. A flea should be capable to chew a handled cat and trigger a FAD response in severely delicate cats. In these instances, it’s essential to remove fleas from the surroundings. Out of doors cats could must be acclimated to an indoor surroundings the place management is more practical.
- Optimize pores and skin well being: Feed your cat an entire weight loss plan that’s balanced for his or her lifestage, and focus on along with your vet whether or not a complement could assist to maintain your cat’s pores and skin in high situation.
Incessantly Requested Questions
How do you deal with flea allergy dermatitis in cats?
The details of remedy are to deal with and take away fleas on the cat and their dwelling surroundings, and to deal with the allergic response. There are various merchandise out there for remedy and prevention of fleas in cats. Cleansing, washing, and treating for fleas within the dwelling will assist the method to go sooner. The allergy response could also be handled utilizing steroids and antihistamines.
How lengthy does flea allergy dermatitis final?
Allergic reactions are lifelong and would require ongoing administration. The rapid allergy response can typically be managed in a number of days in order that the cat is much less itchy and uncomfortable. Secondary pores and skin infections could take 2-3 weeks to resolve on antibiotics so long as the flea drawback and self trauma are addressed correctly. Treating and controlling fleas could take wherever from 1-3 months relying on how closely a house is infested.
What does a flea rash appear like on a cat?
Flea allergy dermatitis classically consists of small crusty pink bumps referred to as papules on the top, neck, and on the again close to the bottom of the tail. If a cat has been scratching at these areas excessively, pink patches of uncooked pores and skin could develop as properly.
How do you soothe flea dermatitis?
First, any fleas have to be eradicated and managed. If a product has been used to kill fleas and not less than 24 hours has handed, a shower to take away lifeless fleas, flea saliva, and flea filth could assist. Oatmeal shampoo could assist calm irritated pores and skin and there are different shampoos designed for pets to assist soothe itchy pores and skin. In lots of instances, a steroid could also be wanted to totally suppress the immune response and alleviate itching. Your vet might want to decide the correct steroid medicine and dose.
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Flea Allergy. (2018, Might 21). Cornell College School of Veterinary Drugs.
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Flea allergy dermatitis in canines and cats. Boehringer Ingelheim. (2024, February 24). Boehringer Ingelheim.