Vet Buzz from Bill Barboni, DVM and Chris Pitts, RVT,
Marin Pet Hospital, San Rafael, CA
We admit it just the word ‘mite’ makes us itchy, not to mention watching your poor dog scratch and scratch is bound to make you itchy too. In the dog world the Sarcoptes scabiei (aka scabies) and Demodex mite are most commonly seen. Luckily, getting rid of these little pests is usually pretty straightforward.
The presentation for both types of mites is itchiness and patchy fur. However, the hair loss for a typical scabies infestation results in patchy fur on the ear tips, legs and belly. The hair loss pattern from Demodex is usually confined to the face and legs.
To diagnose either type of mite, your veterinarian will perform a skin scraping. A scalpel blade is passed across the skin, and the resulting sample is then viewed under the microscope. Even if your veterinarian does not see mites under the microscope, he may prescribe a mite treatment anyway. This is because mites burrow into the skin or hair-shafts, and on occasion it is possible to not scrape deep enough to get a few mites onto the slide.
The treatment for both kinds of mites is similar; a course of Ivermectin. Your veterinarian will determine the dose and duration of treatment. However, certain kinds of dogs have a breed-specific negative reaction to Ivermectin. These breeds include Collies and Australian Shepherds. For these dogs there is an Ivermectin derivative that is can be used instead. If your dog has a weakened immune system, it will take longer to clear the mites. In fact, a delay in recovering from mites may be an indication for your veterinarian to propose further testing for an underlying sickness.
Scabies is contagious from dog to dog. The mites are happy to hop onto a new host and wreak havoc on a new furry beast. Dogs suspected to have scabies should be kept away from other dogs until the veterinarian gives the OK. Demodex are most commonly seen on the young or immune-compromised. This is because the immune system is not vigorous enough to fight off infestation. Demodex are not considered to be contagious between dogs except in cases of suppressed immune systems. Demodex are rarely contagious to people. A person has a higher risk of getting Demodex if he is young or has a weakened immune system.
Sarcoptes scabiei is contagious to people. However, a human is not the preferred host for this mite, and therefore, the infection has a shorter duration in people. Just as with dogs with compromised immune systems, humans with weakened immune systems will have a harder time eliminating mites. If you suspect that you may have contracted scabies or Demodex from your pet, you need to call your doctor, especially if you have a weakened immune system (chemotherapy patients, AIDS patients, and people who have a pre-existing skin disease). Supposedly after thirty-six hours Sarcoptes are no longer viable in the environment, but we recommend washing all bedding or coverings from where your dog likes to hang out to prevent re-infestation.
In conclusion, if your dog gets super itchy and gets patchy fur, get him checked out. Not only will he be really happy you did, but you might prevent yourself from getting some ‘special friends’ too.
As usual, an ounce of prevention is worth a pound of cure.