Pets presented for complaints associated with some pathology of their skin — such as pruritis, abnormalities of keratinization,
alopecia and other abnormalities both primary and secondary — comprise a large percentage of cases seen by veterinarians.
Not surprisingly, parasites are responsible for a great many of these cases, some directly associated with an inflammatory
process following the bite of an external parasite.
Few would argue that fleas are the most common external parasite in dogs and cats. They are virtually universal in their distribution
and have voracious appetites for blood. They feed frequently, necessitating multiple bites that at very least result in a
focal discomfort and commonly produce secondary allergic reactions that can be amazingly severe.
Flea-bite dermatitis and flea-allergy dermatitis can incite secondary problems, such as papular and pustular rashes, self
excoriation and seborrhea as a response to the inflammation. It can be difficult to determine if flea-associated dermatopathies
are primary skin diseases or secondary complicating factors.
Often considered seasonal parasites, fleas are amazingly hardy pests that in their immature stages can survive the most challenging
conditions. They also have an amazing ability to infest locations where the environment is more hospitable, such as places
where animals are housed, areas protected from cold (crawl spaces and under porches), upholstered furniture in homes and even
interiors of automobiles.
In short, fleas are everywhere and must be controlled the year around. Fleas always should be considered in virtually any
skin-associated presentation of a pet, and pet owners must be reminded to always take a preventive approach.
Ticks, too, can play a role in skin diseases. Though not as ubiquitous as fleas, they can survive inhospitable conditions
in sheltered areas. They may play a smaller role in inciting generalized dermatitis, but the site of their attachment frequently
results in a localized reaction.
In the past, fleas and ticks were the bane of veterinarians. Available products were difficult to use, unpleasant and potentially
toxic. They required frequent application and often necessitated environmental treatments, such as household and kennel applications.
Those products left much to be desired.
Today, flea and tick products are far more effective, including systemic compounds, administered orally, that disseminate
insecticide via the bloodstream, topically applied products that are spread over the skin from single sites of application
and growth-hormone regulators that interrupt the life cycle of fleas. All are effective, safe and economical.
It is far easier to prevent infestations and the skin diseases they cause. The best way to do so is through regular, year-round
pre-emptive use of a product for all dogs and cats in a household.
Lice and mites
Lice and mites can result in significant inflammatory responses and can at times be difficult to diagnose. Demo-dectic mange,
scabies, Chyletiella mites and infestations with lice always should be considered and ruled out as initiating or complicating
factors in skin presentations.
Treatments can be challenging and frequently involve treating all pets in the household as well. For treatment protocols,
The role these external parasites play in skin-related presentations is relatively obvious; in fact, their presence often
is sufficient evidence that they are causing disease.
But that is not always the case. The health of the skin is truly a reflection of overall health and the presence of internal
parasites, particularly if an individual is heavily parasitized or particularly vulnerable the effects of parasites, as is
the case in young animals, aged animals or those on a poor plane of nutrition or debilitated by systemic disease.