Symptoms, diagnosis and treatment options

If you see this icon in a fact sheet summary you may be dealing with a life threatening issue. Consult a veterinarian immediately.

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Flea bite hypersensitivity, or FAD, is an excessive reaction to the bite of a flea. When a flea bites and dog or cat (or human) it injects a small amount of saliva into the skin. Normally this produces little more than a mild itching. Some cats and dogs can however develop an allergy to this saliva, and, in these animals, even a single flea bite can cause intense itching and irritation. A severe flea infestation, where lots of fleas or flea dirt is found, can cause the same signs in non-allergic patients.

FAD is most commonly seen in the summer months when fleas are more prevalent but can occur even in winter because even low numbers of fleas can cause a reaction. Pets suffering from flea bite hypersensitivity will continually bite, chew and lick their skin.

SEVERITY: Incurable but treatable.

Dogs typically attack their back, just above the tail, the back and insides of their hind legs, their belly and around the anus. This leads to scabs, hair loss, thickening and increased pigmentation of the skin and scaling and, eventually, to weepy skin and sores.

Cats are affected slightly differently. Some cats develop small scabs over their back or, in severe cases, over their whole body called ‘miliary dermatitis.’ Others lick until they develop bald patches, especially on their belly and the back of their hind legs.

Diagnosis is usually easily confirmed by a visual examination. Conditions other than flea bites may cause similar signs however, so we may recommend tests to confirm the diagnosis, especially when there is no visible evidence of fleas on the animal.

FAD is not life threatening, but nor is it curable. In the short term, hypersensitive pets who have been exposed to fleas and are suffering from FAD need medication to relieve the itching, stop them scratching and give their skin a chance to heal. Some will also need antibiotics for infections that have developed in the damaged skin.

In the long term, all pets suffering flea bite hypersensitivity need to have their exposure to fleas minimised — permanently.

There are several excellent, easy to use products available that effectively kill adult and juvenile fleas both on your pet and in the environment. Where large environmental contamination with flea eggs exists separate environmental treatments may be recommended.

Other pets in the household also need constant treatment. Although they may not be allergic and no be affected, they do carry fleas which then can bite the affected pets. Please talk with our nurses regarding a specific flea prevention treatment program for your pets.



ALL of the articles in this section cover symptoms that require immediate veterinary treatment.

E&OE. The information provided in the articles on this site is intended as a guide to assist readers to become better informed about health issues that may affect their pets and livestock. They are not a substitute for appropriate veterinary advice and treatment. They should not be used for diagnosis or treatment of any individual animal and no person should place reliance on information derived from them, where such reliance may result in loss, damage or injury. Always consult a qualified veterinarian to obtain advice.

Although Alpine Animal Doctors make every effort to ensure that the information contained in our articles is accurate and up-to-date we can accept no responsibility for errors or omissions that may occur.