Effects of Fleas
Fleas are the leading cause of itchiness (pruritis), scratching and severe skin irritation in companion cats. They cause some degree of irritation simply by crawling around. Inevitably, once they settle on a particular cat, fleas quickly begin to dine. They bite into the cat’s skin and feed on its blood. An animal’s physical reaction to a flea bite is really a reaction to the flea’s saliva that enters the bite wound. Some cats have mild reactions to flea bites. Others – especially young kittens and older or sick adults – become severely anemic and gravely ill from loss of blood to fleas. They also may become weak and develop skin sores with secondary bacterial infections. The consequences of flea infestations can be extremely painful. Sometimes, they are fatal.
Symptoms of Fleas in Cats
The most common problems caused to cats by fleas are flea bite hypersensitivity and flea bite dermatitis. Flea bite hypersensitivity is an allergic reaction to substances contained in flea saliva. Cats that are hypersensitive to flea saliva can have horrible reactions from only a few bites. They become intensely and uncontrollably itchy, often scratching, chewing and digging at their own skin in attempt to relieve the discomfort. Flea bite dermatitis is a result of direct irritation at the site of flea bites. The areas most frequently affected are the back, rump, thighs, tail base, belly, flanks/groin and upper arms (especially under the arm pits). Owners of cats with a flea problem may see one or more of the following signs:
- Scratching; may be severe (intense itchiness; “pruritus”)
- Skin abrasions (sores) - often red, raised, raw, weeping and/or bloody (erythematous crusted papules; often around the neck and back; miliary dermatitis)
- Pus oozing out of skin sores (pyoderma) – from secondary bacterial infection
- Lip ulcers or sores (eosinophilic granuloma complex)
- Excessive grooming
- Patchy areas of hair loss (alopecia)
- Vomiting hairballs (gastric trichobezoars)
- Tapeworm larvae around the anus and in the stool (look like rice; larvae of Dipylidium caninum, a common tapeworm in pets)
- Black pepper-like flecks on the skin or in the coat – indicate the presence of flea feces (“flea dirt”)
- White salt-like flecks on the skin or in the coat – indicate the presence of flea eggs
- Weight loss; poor coat and body condition
- Adult fleas visible on the cat
A cat’s self-mutilation in reaction to flea bites can set the stage for devastating secondary bacterial skin infections. Many cats that aren’t allergic to flea bites still develop severe flea bite dermatitis from the mechanical skin irritation caused by these nasty bugs.
Fleas can carry and transmit a number of potentially serious diseases. They are intermediate hosts for Dipylidium caninum tapeworms. Cats that ingest adult fleas while grooming or chewing are at high risk for becoming infected with tapeworms. Children can also get tapeworm infections if they accidentally get fleas into their mouth. Fleas can carry other infectious microorganisms, including those that cause plague (Yersinia pestis), tularemia (Francisella tularenis), typhus (Rickettsia) and myxomatosis (Leporipoxvirus, which causes severe generalized disease in rabbits).
Cats at Increased Risk
Cats living in hot, damp climates in close quarters with other animals are at increased risk for becoming infested with fleas. Fleas thrive in those environments and, because of their remarkable jumping ability, often leap from one animal to another. Cats living in colder climates usually develop a flea problem only in the warm months. Indoor cats in flea-infested homes will have year-round symptoms.