Sep 19, 2019
The flea bite is a problem for a variety of populations — from
those in natural disaster scenarios to pet owners. Dr. Vincent
DeLeo talks with Dr. Dirk M. Elston about
cat fleas and other issues in environmental dermatology. Dr.
Elston discusses vector-borne diseases, including endemic typhus
and cat-scratch disease, caused by organisms transmitted by fleas,
as well as interventions to remove fleas and treat their bites. Dr.
Elston also gets personal and talks about how he got interested in
bugs following his time in the military.
We also bring you the latest in dermatology news and
States pass record number of laws to reel in drug
Measures include authorizing imported prescription drugs,
screening for excessive price increases by drug companies, and
establishing oversight boards to set drug prices.
Peanut allergy pill gets thumbs-up from FDA advisory
The approval of Palforzia is on condition that a black-box
warning and medication guide are included in the packaging.
Henry W. Lim takes a closer look at new data on
Things you will learn in this episode:
- All fleas are vectors for disease in humans. “You see dog fleas
on cats, and cat fleas on dogs,” Dr. Elston explains. “You’ll see
poultry fleas on dogs, especially in the Carolinas. But there are
certain fleas that historically have been the ones that carry most
- Cat fleas (Ctenocephalides felis) can carry endemic
typhus and are typically found in south Texas and southern
California. Oriental rat fleas are a vector for disease in other
parts of the United States, including areas of California and the
- One of the clues for identifying endemic typhus would be a
small rickettsial or black depressed eschar at the site of the
- Flea bites — presenting as papular, vesicular, intensely
pruritic— tend to occur on the lower parts of the body. “The fact
that they’re grouped on the lower extremity, the papular vesicular
or bolus quality does suggest the possibility of fleas,” reports
- For houses or abodes that have long been unoccupied (e.g., 2-3
years), new owners walking on the floorboards may rapidly activate
the pupae living in them.
- Flea treatments for animals include fipronil, which is applied
on the animal’s neck and spreads like an oil over its body. Oral
agents containing ivermectin for heart worm and fleas; however,
ivermectin can be fatal for some animals, such as collie dogs.
- Disease depends on the type of vector. “If you have the
organism transmitted by a louse, you’re likely to get
endocarditis,” Dr. Elston explains. “Whereas if it’s a flea, you
are more likely to get cat-scratch disease rather than sepsis and
- Long-term therapy with macrolides is a mainstay treatment of
cat scratch disease.
- Children with cat-scratch disease who present with systemic
disease, including neurologic disease, should be managed together
with an infectious disease specialist.
Guests: Dirk M. Elston, MD (Medical University
of South Carolina, Charleston); Henry W. Lim, MD (Henry Ford
Medical Center, Detroit)
Show notes by Jason Orszt, Melissa Sears, and Elizabeth
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