Have you ever heard of Delusional Parasitosis? It isn't very common, but is a very real issue that you may come across in vet practice. 

This is a human disease or syndrome, where an owner believes that they or their pets are infested with a parasite or organism that isn't there.

It is a mistaken belief that one is being infested by parasites such as mites, lice, fleas, spiders, worms, bacteria, or other organisms.

Most of us, being compassionate and understanding people, want to help them to understand the reality of the situation but without causing drama or hurting feelings.

We want them to feel that their pet is safe and protected and that they no longer need to worry about these supposed parasites hurting their pet.

Let's Work through a Scenario:

• A middle-aged woman client presents her 5-year old male neutered dog for being infested with bugs. She has found them on him and all over the house. She cannot seem to get rid of them.
• She has determined that two different species of insects are now breeding in her house and this is causing a serious infestation. 
• You examine the dog closely. There is no erythema, pruritis, hairloss, or lesions of any kind. You perform a courtesy skin cytology on the dog, and examine a sample of the "parasites" she brought in under the microscope.
• It appears as if this is just organic material, or possibly even cigarette ash based on the appearance. This is called the "matchbox sign," when an owner brings in various things to have examined- such as skin flakes, ashes, dust, or other small particles.
• No one wants to call someone else crazy. This is a very sad disease that can cause a great stress to the owner. So, what should you do in trying to do the best thing by the pet and the owner?

1) Conduct an Appropriate Work-Up

Do an appropriate work-up on the dog- skin cytology, and examine the samples the owner brings in. Take the time to show them under the microscope that there are no organisms involved.

2) Be Careful about Prescribing Medications

If the dog doesn't need medication, you shouldn't send any. I have concern that an owner may over-medicate if they continue to see these organisms in their house or one their pet.

3) Help Repel Insects

Yes, you can send some Repel wipes or something benign to help repel any insects.

4) Be Honest with the Owner

Tell the owner you have done a complete workup and there is no evidence of parasites.

5) Provide Handouts

You may consider printing an article or client handout on this issue. We cannot diagnose humans, but it is important for them to seek medical help for this condition themselves and know that they are not alone and their may be an answer or treatment for them.

6) Have them Call Pest Control

This way someone physically comes to their house and can tell them what they find. If they do not find anything, this will help to support your theory.

Here are several fantastic resources on this topic:

• Delusional infestation by proxy — What should veterinarians do? 
• When people's delusions affect pets-from VIN
• Delusional Parasitosis - from UC Davis
• Successful Treatment of Delusions of Parasitosis With Olanzapine - JAMA Dermatology (with human case studies)