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Dr. B.
Dr. B., Veterinarian
Category: Dog Veterinary
Satisfied Customers: 21416
Experience:  Hello, I am a small animal veterinarian and am happy to discuss any concerns & questions you have on any species.
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My cavalier has dark spots on the inside of her legs and

Customer Question

my king charles cavalier has dark spots on the inside of her legs and tummy and I'm not sure why? She also has red spots on her leg where she has been itching because of flea irritation. She and our cat have been on flea meds for 6 months now and I still can't get rid of them! I have also used flea baking soda treatment to carpets as well and have had flea control come out and spray now twice.
Submitted: 2 years ago.
Category: Dog Veterinary
Expert:  Dr. B. replied 2 years ago.

Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you with your wee one today.

Are they raised or flat?

Is there redness around them?

By spots, do you mean that she has pimples or pustules?

Are you still seeing the fleas? Or are your pets just itchy?

Did the spray used on the house contain insect growth regulator?

Customer: replied 2 years ago.
No they are not raised but flat and originally I thought is was just dirt from playing outside. No redness around. She is itchy often and because of that is creating a hot spot on her leg. I used to see fleas but haven't in a few weeks. Yes insect growth regulator was in the spray. Should I just use it again hoping they will completely go away? Our vet says she may have a flea allergy but what are the dark spots?
Expert:  Dr. B. replied 2 years ago.

Thank you,

With a history of skin issues here, the black spots you are seeing are most suspicious of hyperpigmentation. This is just a phenomena that arises when the skin has been chronically irritated such that the local skin melanocytes produce excess pigment in the skin (its similar to why we tan when the sun "irritates" our skin). It is essentially a side effect of her skin itchiness.

Now if you are not actually seeing fleas, then I agree with your vet that we are now just seeing the effects of the allergy. For sensitive dogs, they need only to be bitten once (and the flea could be now dead) but their immune system reacts in such a way that it can leave them itchy for weeks. And as they scratch the itch, our dogs actually irritate their skin more and cause secondary infections (like the hot spot) which are even itchiness. So, instead of necessarily treating for fleas again just now, it would be ideal to treat the allergy. So, if you have not already, you can consider starting her on an antihistamine. Most commonly we use Benadryl/Diphenhydramine (More Info/Dose @ low dose (ie. 0.5-2 mg per pound of their body weight twice daily) can just be enough to reduce that allergic irritation. We like to keep the dose low, as it can cause drowsiness (just like people). And of course, this medication shouldn't be used if your wee one has any pre-existing conditions or is on any other medication without speaking to your vet first. Otherwise, if you have tried this already or if she is severely itchy, then we'd want to speak to her vet about a short course of steroids to halt this allergic reaction.

Overall, if you have not actually seen fleas for a few weeks, I do suspect that Penny's continued itch is related to the allergic reaction still raging in her skin. So, we'd want to address that for her. And if we do quickly, then we should see the hyperpigmentation settle with time. Though I would warn that if this is allowed to get severe, we can see permanent (but non-harmful) discoloration of the skin.

All the best,

Dr. B.


If you have any other questions, please ask me – I’ll be happy to respond. Please remember to rate my service once you have all the information you need as this is how I am credited for assisting you today.Thank you! : )

Expert:  Dr. B. replied 2 years ago.
Hi Amanda Boschken,
I'm just following up on our conversation about Penny. How is everything going?