Flea Allergy Dermatitis – One Little Bite Can Be Torture


Flea bites cause annoying itching and inflammation for dogs and cats. But if your pet is one of the many that suffer from an allergy to flea bites (known as “flea allergy dermatitis”), a single flea bite can be sheer torture.

It’s not the bite… it’s the saliva

Pets with flea allergy dermatitis are actually allergic to certain proteins in the flea’s saliva, not the actual bite. The flea injects saliva into the skin when it bites and feeds off your pet. The proteins in the flea saliva produce painful itching reactions so severe that these pets will literally bite and chew their skin raw.

These pets have a hypersensitivity to flea saliva that is so extreme it takes only one little flea bite for them to become symptomatic.

What are the symptoms of flea allergy dermatitis?

If your pet shows any of the symptoms below, act quickly. Left untreated, flea allergy dermatitis can lead to yeast and bacterial infections.

  • Scratching, chewing, or licking of the skin
  • Whining
  • Restlessness
  • Rolling on the back to scratch itchy areas that can’t be reached by the paws or mouth
  • Redness and inflammation of the skin
  • Unpleasant odor from infected areas of the skin
  • Scaling or crusted patches on the skin
  • Flea dirt in affected areas (flea feces containing small pieces of your pet’s dried blood)
  • Bumps on the skin in the affected areas, especially on the back and tail
  • Raw areas and bare spots in the coat where the skin has been broken from constant scratching and chewing
  • Open wet sores, often with pus

Flea bite allergies are more common than you might think. In fact, this is the most common type of allergy seen in cats and dogs.

It is not unusual to find no presence of fleas on a pet with flea allergy dermatitis. The pet usually removes the fleas during grooming, and the only evidence of the flea will be the “flea dirt” that is left behind. Brush your pet thoroughly over a white surface. If any debris falls off, slightly dampen it. Any reddish-brown streaks that appear are your pet’s blood.

What is the recommended treatment?

The best solution is to stop fleas before they can bite. For most pets, a monthly flea preventive will keep fleas away. You should start flea protection at least one month before flea season begins. Continue the treatment throughout flea season and for one to two months after flea season ends. During cold winter months, fleas can survive inside your home. If your pet has been on a reputable preventive medication from your veterinarian and still has fleas, the source may be wild animals taking refuge in your attic.  Even a quick trip outdoors makes your pet a target for fleas, and humans can unknowingly carry fleas into the home too.

Once you have a flea problem, it’s extremely important to treat it quickly and aggressively. This requires two levels of protection – you must treat both your pet and your home.

There are three goals to this treatment:

  • Kill the fleas on your pet – There are many products designed to kill adult fleas on your pet. The topical and oral  products available from your veterinarian are safe and extremely effective. If you have more than one pet in the home, you must treat ALL the pets in your home, not just the ones who suffer from flea allergy dermatitis.
  • Eliminate flea infestations in the home environment – If you don’t see any actual fleas on your pet, don’t assume that you don’t have a problem. Most fleas live inside your pet’s bedding, in your rugs, and in the areas between sofa cushions and baseboards. Keep your pet’s bedding clean. Frequently vacuum the areas where your pet sleeps. Vacuum between sofa cushions and along baseboards. Throw out the vacuum bag when you’re done or empty the contents of the vacuum into a bag and immediately remove it from the home. Because fleas spend most of their time on your pet, effective control of fleas on the pet is usually sufficient, unless the infestation is severe.
  • Prevent new flea infestations – Use a monthly flea preventive on all your pets. There are many effective products available, but ideally choose one that kills adult fleas and has an insect growth regulator (IGR) to kill flea eggs or larvae before they have a chance to mature.

Flea allergy dermatitis is painful condition that takes a real toll on our pets. In some cases your veterinarian may recommend antihistamines, steroids, antibiotics, anti-inflammatories, or anti-fungal medications to treat painful symptoms and infections.

Eliminating fleas on your pet and in the home environment takes continued effort on your part. It can take several months to get an active flea problem completely under control. The best prevention for flea allergy dermatitis is comprehensive prevention during the flea season in your area.