Valley Fever in Dogs: Diagnosis and Treatment

Monsoon Storm

Monsoon Storms can increase dogs’ exposure to Valley Fever.

Our friend Jodie over at Happy Dog Phoenix recently asked me about the health risks associated with summer dust storms. Answering her question got me thinking about Valley Fever. Most dog owners in Arizona have heard about this disease. This should come as no surprise, since one study estimates that nearly four out of every 100 dogs living in Maricopa and Pima counties will get sick from this disease each year. On the up side, the same study showed 70% of dogs that are exposed to Valley Fever don’t get sick.

Valley Fever is caused by a fungus called Coccidioides immitis; we call it “Cocci” in veterinary slang. Cocci is a mold that grows in the soil. When it matures, it sheds microscopic spores that are inhaled when dogs dig, sniff holes in the desert, or are exposed to blowing dust during a haboob. Signs of infection are non-specific. This means many different diseases can cause the same symptoms: lack of energy, poor appetite, weight loss, cough, fever, limping, and seizures. This is why Arizona veterinarians start thinking about Valley Fever as soon as they meet a dog that’s “ADR” (more slang… “ain’t doin’ right”).

Want to read more about Valley Fever? Check out this printable information sheet or visit the Valley Fever Center for Excellence website.

Valley Fever is usually diagnosed with blood tests and X-rays. The blood test for Valley Fever detects antibodies against the fungus. Antibodies are proteins the immune system makes in response to a foreign invader. The test isn’t perfect, though. Those 70% of dogs that get exposed? Yeah, they make antibodies, too, so many dogs test positive even though they aren’t sick. And some dogs with Valley Fever don’t make any antibodies and test negative even though they’re infected. That’s why a full blood panel and X-rays are so important. Valley Fever is diagnosed based on a body of evidence: history, symptoms, a general blood panel, X-ray results, AND a Valley Fever test. If everything else supports the diagnosis despite a negative Valley Fever test, we’ll often start treatment and see how the patient responds. If they get better, chances are they DO have Valley Fever, no matter what the test says.

Most cases of Valley Fever respond well to treatment with an antifungal drug like fluconazole. Treatment takes several months in most cases, but the availability of generic medication has made treatment very affordable over the last 10 years. We usually treat for three to six months before repeating the Valley Fever test. A decreasing antibody level and vanishing symptoms generally indicates that the patient is responding to treatment. Antifungal drugs don’t kill Valley Fever, though; they just stop the fungus from growing. It’s up to the patient’s immune system to kill the disease. In some cases, the body isn’t up for the job; these dogs may need lifelong treatment. Some dogs die despite treatment, but thankfully this is the exception rather than the rule.

Preventing Valley Fever is tough. There’s no vaccine, and treating the soil is impractical. Reducing activity that generates dust (like digging) and sniffing in rodent burrows, as well as keeping dogs indoors can all reduce exposure. Grass and deep gravel, which reduce dust, can both limit exposure to the fungus, which can live up to 12 inches below the surface. Dogs that roam over more than one acre of land and those that spend 80% or more of their time outdoors are five to six times more likely to be infected.

Nearly every part of the United States has a unique fungal disease that affects pets; Valley Fever is ours. It’s as Arizonan as the saguaro and rattlesnakes, and it’s here to stay, so be on the lookout for symptoms and do what you can to limit your dogs’ exposure.

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  1. Von says:

    Is there anything I can do to help my dog be more comfortable. Is it bad for her to be out in the heat. Is milk bad to give her. Is it good to keep her cool like lots of baths.

  2. Von says:

    She has vally fever and she is on her third day of medication.

    • Dr. G says:

      Hi Von, I hope your dog is feeling better. Valley fever can be rough! This time of year, the heat in Arizona can be deadly. While it’s not clear where you live, since valley fever is found mostly in the Southwestern US deserts, I’d encourage you to keep her indoors. As a general rule, adult cats and dogs don’t tolerate milk well, and anything more than a couple laps can cause stomach upset. Finally, too many baths in a short period of time can cause a pet’s body temperature to drop to unhealthy levels. Frequent bathing can contribute to skin and ear problems, as well. I’m glad your dog has been diagnosed by your family veterinarian and started treatment. Your family vet is your best source for answers to this sort of question; give them a call!

  3. Lori says:

    I adopted an senior basset with valley fever. He caught it as a puppy and wasn’t able to get over it. He is now 15. He has been taking fluconozol and vitamin c. But at over $1.00 a pill it is expensive. Are there any alternatives? We live in Colorado so the vets here don’t know much about the disease.

    • Dr. G says:

      Hi Lori,

      Despite recent increases in the cost of generic drug, fluconazole provides the best balance of effectiveness, reliability, safety, and cost. While there are other options, most aren’t as effective, and many are actually even more expensive than fluconazole! Your family veterinarian may want to consult a specialist in internal medicine or infectious disease, or contact the Valley Fever Center for Excellence in Tucson, since Valley Fever is pretty uncommon outside the desert southwest.

  4. Mary Hanson says:

    Can Ihma be indicative of valley fever in dogs?

    • Dr. G says:

      Hi Mary,

      Secondary immune-mediated hemolytic anemia can be initiated by a number of infections, allergies, and other processes involving the patient’s immune system. While we have no direct experience with valley fever causing IMHA in one of our patients, it’s possible in theory.

      This said, IMHA is not a typical symptom of valley fever in our experience.

  5. Trista says:

    My dog has major difficulty walking due to the fungus in his joint. Is there any relief for that? He is already on th Fluconazole and has been for almost a year

    • Dr. G says:

      Hi Trista,

      Valley fever infections in bones or joints can be very painful. Please talk to your veterinarian about adding appropriate pain relief to your dog’s treatment regiment. If x-rays haven’t already been performed, you should also ask to have some taken to rule out other causes for the lameness, particularly since it hasn’t responded to fluconazole so far.

  6. Nancy says:

    My dog was diagnosed with Valley Fever 1 1/2 years ago and has had fluconosol during this time. Her titers are now a 1:2 Her vet suggests that she be on the meds for another 3 to 6 months? Your take please.

    • Dr. G says:

      It’s common practice to treat with antifungal drugs for 3-6 months after the titer drops to 1:2.

      We do this because it’s very difficult to tell when it’s wise to discontinue treatment–and any vet who’s practiced in AZ for more than a few years has seen a case come back with a vengeance after stopping treatment. Titer testing measures the amount of antibodies in the blood, so it’s measuring the body’s response to infection. Decreasing titers usually correspond to improving symptoms, but there is no established standard for how low is “low enough” to stop treatment, so each veterinarian’s protocol for stopping treatment is based on their personal experience.

      • Willy says:

        can you just stop treatment or is it wise to taper off the medication?

        • Dr. G says:

          Hi Willy,

          While there is usually no need to taper the medication, you should consult with your veterinarian before stopping. The decision to discontinue treatment is usually made based on Valley Fever test results as well as the patient’s clinical condition.

  7. Kat says:

    Hiya, my 6yr old mastiff Rufus has been on fluconizol and phenobarbital for 4 years. We also give him adenosyl 250mg and nuroplex twice a day….every day. His valley fever affected his brain, seizures he gets monthly. Once in a while he will get clusters that last for days…5 to 25 sec seizures and loss of sight.
    My question is aside from pills and supplements, is there anything else we can do to help him. I also cook natrual food for him his snacks are vegetables, and his water is clean.

  8. Sheryl Boone says:

    Our dog Sandie had V.F. has been treated by our Vetranarian I’m wondering if I should putt her back on the Tramadol for joint pain , she still has a Cough and is drinking alot of water which afterwards she coughs every time . Treatment w/Antifungal med 1yr +

    • Dr. G says:

      Hi Sheryl,

      Sandie’s current cough could be due to a number of things. Sounds like it’s time for a follow-up visit with your family vet to determine what the cause is. They’re the best source of recommendations for pain control, as well.

  9. Cindy says:

    My dog was first thought to have kennel cough, but when he didn’t respond at all to the medication, the vet said his symptoms are similar to those with valley fever. My dog has been on the valley fever medication for almost two weeks, and I have seen almost no change in his condition. How much longer should I wait before I raise concerns over my dogs incessant coughing and joint pain?

    • Dr. G says:

      Hi Cindy,

      Your family veterinarian is counting on you to get in touch whenever you have a health concern related to your pet–especially if they’re not responding as expected to a new medication. Give them a call today!

  10. Suzann says:

    My 9 year old dog was just diagnosed and has been Fluconazole for about a week. I was curious as to if/when he should show signs of improvement? He has a very dry cough so we have had to add a cough medication to his treatment. The coughing takes it’s toll on him and i just want to know if he’ll have at least a little relief soon. He is also diabetic and takes insulin, has glaucoma due to the diabetes and has arthritis also. It’s a lot to deal with for him, is there anything i can do to help relieve some of his stress?

    • Dr. G says:

      Hi Suzann,

      While every pet is different, most will show signs of improvement within a couple weeks of starting treatment with an appropriate dose of fluconazole. Diabetes can weaken pets’ immune system, so it’s important that you keep in close contact with your family veterinarian during treatment.

  11. Daphne says:

    I just found out my 9 month old puppy has valley fever, we don’t know how long she has had it she only had swollen glands that was the only thing going on with her doing great with every thing else,will she ever get it again,if she lives through it

    • Dr. G says:

      Hi Daphne,

      Unfortunately, natural infection with Valley Fever does not confer future immunity to pets or people after they recover; they can get sick again if they are exposed later.

  12. Shawna says:

    Our Boston Terrier had VF about 3 years ago. She was on Fluconazole for about a year, and her titer dropped to 1:2 so treatment was discontinued. A few months ago she presented with lameness (walking on eggshell gait) and her ankles swelled a bit. She had a full panel of blood tests including Lyme disease and Tick Fever, and her VF test once again came back 1:2. All her blood tests were negative and WNL. She then was diagnosed with polyarthritis and treated with prednisone, which immediately relieved all her symptoms. She began on a dose of 10mg 2xday, which seemed too strong after 2 days as she was having urinary incontinence. She was reduced right away to 5mg 2xday, and continued on a tapering dose (in two week increments) for almost two months, and which just 4 days ago was decreased again, to 1/4 tab of a 5mg tablet once per day. She had a moment today of ‘walking on eggshells’ again, but it seems to have resolved. I know that she might need to be on predinose for life, but this is such a strong medication with side effects. I can handle her weight gain, but when she’s on the higher doses she just seems less enthusiastic about life. Throughout this entire process there is a little part of me that keeps wondering if this might be polyarthritis brought on by the VF. It’s really nagging at me. I know that her blood tests were negative and WNL, but is there even the smallest chance that she is just the rare atypical case of VF? If there is, I would rather try fluconazole again to relieve my concerns once and for all before I commit her to a life-long regimen of predinose. Fluconazole seems the better of two evils…

    • Dr. G says:

      Hi Shawna,

      Sorry to hear your pup is having problems! Polyarthritis is a possible, but uncommon symptom of Valley Fever. More typically, it causes osteomyelitis (infection in the bone). Your family veterinarian is the best point of contact for your questions. You might also request a referral to a specialist in veterinary internal medicine if your concerns can’t be addressed adequately.

  13. Laurie Lobins says:

    My 2 yr old Italian Mastiff was just diagnosed I think VF. His titers were 32. How bad is this and also what is the difference between fluconizole and boraconizol? Should I be giving him milk thistle to prevent liver damage? Thank you so much.

    • Dr. G says:

      Hi Laurie,

      Valley Fever titers indicate exposure to Valley Fever and how “robust” the immune system’s response is, but they are not a good measure of how serious an infection might be. Information on the pros and cons of various treatment protocols for Valley Fever can be found on the VFCE’s website. Please consult your family veterinarian before using any supplements. Even “natural” remedies can have side effects!

  14. Melanie says:

    I rescued a bull terrier from Arizona and now live in Washington state.
    She had her titer and was deemed clear to stop Fluconazole. But the weather is hitting -16 celsius and I’m not sure if her congestion and runny nose is due to that, or Valley Fever making a comeback. Her breath has been unbearable lately and she’s had gum issues that I haven’t fully resolved with professional cleaning and my own cleaning.
    If I were to get her bloodwork done again and she had to go back on the drugs, what could I do to help her be more comfortable and healthy during the regimen? i.e, vitamins, change proportions of fat/protein in food, bathing, exercise, etc.
    And if she is just having a little cold from the temperature shock (we keep her indoors with a humidifier as much as possible) then what other things should I do to keep her from developing a bout Valley fever again?

    • Dr. G says:

      Hi Melanie,

      Without the benefit of a thorough physical exam, it’s impossible to tell what might be causing your pup’s symptoms. I’d encourage you to bring your concerns to the attention of your family veterinarian. Outside of the southwest, most primary care veterinarians aren’t too familiar with Valley Fever. You might consider asking for a referral to a veterinary internal medicine specialist if your vet needs additional help.

  15. Billie dunlavey says:

    My dog was diagnosed with valley fever in late October with a very bad case . She has been on fluconozole since . She saw slow progress too recently now she seems to be very congested again and coughing a lot and seems to be going backwards in treatment . Would re exposure cause thus ? If not then what ? Could I t be h re natural immune system giving up ? She is a 6 year old beagle

    • Dr. G says:

      Hi Billie,

      Whenever there’s a change in a pet’s response to medication, it’s always best to contact your veterinarian right away. There are a number of things that can cause respiratory symptoms that aren’t related to Valley Fever, so it’s possible that this is a new problem that should be appropriately diagnosed and treated. Please give your family vet a call right away.

  16. boo ross says:

    Hi, my 5 year old medium mixed breed got bitten twice in four days by rattle snakes and needed treatment and antivenin on the second occasion. He seemed to make a full recovery and then got pancreatitis two weeks later and valley fever showed up in the tests. He is almost 8 weeks in now and the pancreatitis cleared up and he is on fluconazole, which could only be started after the pancreatitis cleared up which was about 3/4 weeks ago. His appetitive is improving with some creative meal making for him, and other than a cough when he gets excited he seems to be regaining his bubbly personality. My question is when can he start to exercise again? He has been resting at home when we take our other two dogs out for a walk in the desert every morning, and is becoming increasingly excited to come with us each day! He then sulks when he can’t come!! I’d obviously only like to exercise him when it’s safe to do so. The other two dogs show no signs or symptoms luckily.

  17. Jennie Wright says:

    Hi my 5 yr old dog has just been dignosed with valley feaver and his test indicated that his levels were 1 to 128. Is that really bad. How long has he been sick. Symtoms just started a couple weeks ago. Im hart broken. I love him dearly. It is so hard for me to think hes been for long. But its seems that its high. He is the 3rd puppy from his litter to become ill with valley feaver. One has died alreasy. His mom and dad live with us could they too have it. Im over whelmed. Cant afford the 220 per test. I dont know what to do.

    • Dr. G says:

      Hi Jennie,

      I’m sorry to hear your dog is sick. The titer level (of 1:128 in your case) doesn’t give any information as to how long a pet has been sick or how serious the illness is. Some pets with high titers have mild signs of illness, while others with low titers can be extremely ill. Please continue to work with your family veterinarian to find a way to continue caring for your pets that fits within your family’s budget.

  18. Irene wasson says:

    We come to AZ in the winter. We have an Aussie and seems okay but every now and then he coughs deeply but only one cough. He’s had the kennel cough shot. Should we wait awhile to see a vet?

    • Dr. G says:

      Hi Irene,

      An occasional cough in the absence of any other signs of illness could be due to any number of things. If the cough persists, please consult a veterinarian and be sure to tell them you visit Arizona regularly. Most veterinarians outside of the southwest are unfamiliar with Valley Fever and may need guidance; the Valley Fever Center for Excellence is a great resource for pet owners and professionals alike.

  19. Christa says:

    I adopted a surrendered dog 1.5 weeks ago. Before the first week was over he developed a cough, then loose stools, lack of appetite. A vet visit, blood tests, X-rays and stool test revealed Valley Fever (we live in Tucson) and Giardia. This small dog is estimated to be 8 to 10 years old.

    I have been told by knowledgeable neighbors to have the dog put to sleep – a real heart breaker for my husband and I. But I am of a mind that it often is a kindness to the pet, unlike the drawn-out suffering that we inflict on humans.

    I would love to hear your opinion. Thank you

    • Dr. G says:

      Hi Christa,

      Valley Fever carries a good to fair prognosis for treatment, and I would encourage you to pursue the course of treatment recommended by your veterinarian if it can be worked into the family budget and your new pal is responding favorably.

  20. Tom says:

    To Dr. G or whom it may concern,
    I have a seven year old Doberman Pincher who started to limp. I took her to the veterinarian, and they took X-Rays and drew blood and sent it to the lab to be checked for valley fever or cancer. I was told it will take three to five days for the results. Then after the fifth day I was told five to seven days. Day seven still no results. My dog has been on pain killers since day one. It seems like they don’t do much for the pain. I don’t know how much longer it’s going to take for test results. It looks like her left front shoulder is swollen. I am getting this feeling my veterinarians office isn’t being very helpful.
    Thanks, Tom

    • Dr. G says:

      Hi Tom,

      You sound frustrated, and understandably so. The 3-7 day timeline for reporting Valley Fever test results isn’t unusual, though we always try to set expectations that will account for an occasional unforeseen delay in processing. Please give your vet a call today and check in–not only about lab results but also to let them know your concerns about your dog’s ongoing pain, any new symptoms, etc. I’m confident they’d want to know about these changes and can make some adjustments to the current treatment plan if the results aren’t yet available. Good luck with her. Having had the experience of having to differentiate between Valley Fever and another serious illness with my own dog several years ago, I know just how nerve-racking the process can be!

  21. Jackie says:


    My Dog has valley fever. He is being treated and it is going well. A friend recently told me that letting my dog run around in the dusty ground could lead to making his valley fever worse. My question is whether or not a dog’s valley fever can get worse from the environment. Ie. Can new valley fever spores make a dogs current valley fever worse. I hope that makes sense. Thanks for your help.

    • Dr. G says:

      Hi Jackie,

      The way Valley Fever medications like fluconazole and itraconazole work is by inhibiting fungal growth. It’s unlikely that spores your dog may be exposed to during treatment will make him worse, because the spores should not be able to grow and cause illness.

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