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Why is my dog's leg still swollen after starting doxy for tick disease?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed | Male | unneutered | 8 years old | 30 lbs

Hello doc, How long does it for doxy to start working inside dog system in case of tick fever ? My dog has swollen front leg after 3 days of doxy. This is not coz of doxy as 2 weeks before treatment hes hind leg was swollen wich resolved with lasix. Now after 3 days of treatment hes front leg began to swell. Is it that doxy has not yet started working ? Why he gets such unexplained swelling ? I'm attaching blood report prior to treatment. Plz help as my vet is gone outstation.Thanks in advance

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4 Answers

Most Helpful Answer

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Answered By Susan England-Foster

Veterinarian

Published on October 18th, 2017

I am sorry Scooby is not feeling well. Typically this swelling is called edema. Edema is when fluid accumulates and can be due to many things. The test results you posted do not have tick titers. If you are concerned about tick disease I would test for tick titers. Also another piece of information that would be helpful is a protein level. When protein levels are low it allows edema. The doxycycline itself will not cause edema. However if Scooby does not have a tick born disease it is possible the doxycycline is not going to be useful in solving his problem. I hope that helps

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Other Answers

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    Answered By Dr. Dayna, DVM, CVA

    Veterinarian, Certified Veterinary Acupuncturist

    Published on October 20th, 2017

    Vasculitis can absolutely be caused by tick born diseases. Sometimes steroids are used with the doxycycline to decrease the inflammation in the body. I would recommend either calling or going back for a follow up visit to discuss that possibility. Best of luck and I hope he improves quickly.

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    Answered By Lauren Kennedy, DVM

    Veterinarian

    Published on October 20th, 2017

    Since your dog has only been on the Doxy for 3 days I would give it some more time to work. Typically a tick borne disease needs to be treated with antibiotics for 30 days so you still have a ways to go with treatment. If the swelling is making your dog uncomfortable or making it difficult for him to get around, I would recommend asking your vet about an anti-inflammatory pain reliever (like Rimadyl or Deramaxx) to administer along with the Doxy. This should help him feel better more quickly. I hope this helps. Thanks for using Petco Pet Education Center, formerly Petcoach. Best of luck!

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    Answered By Laura Johnson VMD

    Veterinarian

    Published on October 16th, 2017

    HI, thanks for using Petco Pet Education Center, formerly Petcoach! Poor Scooby, it sounds like he has been through a lot! I am assuming you mean "tick" fever and not teak fever. Tick diseases can cause immune mediate destruction of red blood cells and platelets. They can also cause vasculitis or inflammation of the walls of the vessels thus making them leaky and causing edema (swelling). If the swelling is developing on the doxycyline I would have Scooby rechecked and have his blood work repeated to see what his blood proteins are doing, specifically the albumin. If the blood work is stable he just may need more time on the doxycycline. In the US we treat for 30 days for tick borne illnesses. I hope this helps and I wish Scooby a speedy recovery!

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