Does Your Dog Have a Mold Allergy?

Molds are usually harmless in small quantities, but they can cause problems if a dog is sensitive to them and suffers an allergic reaction. Here’s what you need to know about dogs and mold allergies.


One of the most common skin diseases that develop in dogs is atopic dermatitis. Most of these cases are caused by allergies to substances in the environment. Dog owners are aware of the possibility that their dogs may have environmental allergies to plant pollen and dust or dust mites, but may be completely unaware of one more very significant environmental allergen that can cause ill effect on susceptible dogs: mold.

Molds are a type of multicellular fungi that are present almost everywhere in the environment including the air; favored surfaces include wood, leaves and plants, air ducts, soil, and basements. They thrive in moist, damp, and humid environments, multiplying through microscopic spores that disseminate through the air. Because dogs tend to explore environments – especially with their noses – they can be at increased risk for coming into contact with and inhaling mold spores. 

Molds are usually harmless in small quantities, but they can cause problems if a dog is sensitive to them and suffers an allergic reaction. An allergic reaction occurs when the dog’s immune system responds to a substance with a state of over-reactivity or hypersensitivity. If the allergy becomes chronic, it can become uncomfortable and even painful; if not treated, it can lead to the development of more severe health issues.

Symptoms of mold allergies in dogs

Dogs allergic to mold typically develop a year-round skin problem. If they are allergic to mold, the symptoms may wax and wane with atmospheric humidity (which allows molds to reproduce at a faster rate) but will be present to some extent year-round, because the offending allergen is present all the time, not just seasonally like some pollens. This allergy is most likely to develop in dogs between the ages of 6 months and 3 years, however, dogs can develop an allergy at any time during their lifetime. 

Mold allergies tend to manifest as a skin condition. Symptoms may include scratching (often persistent), inflamed and irritated skin; dry scaly skin, localized or generalized hair loss, chewing/licking (especially the paws); chronic ear infections. It is also possible, but uncommon, for molds to cause respiratory symptoms such as coughing, sneezing, wheezing, labored breathing, discharge from nose and/or eyes, and even loss of appetite and lethargy in more severe cases. Dogs with mold allergies are also frequently affected by other inhalant allergens, such as mites.


Mold allergies cannot be distinguished from other types of allergies without allergy testing, but your veterinarian may first want to perform a thorough exam, obtain a history, and perform other diagnostics to determine if the presenting condition is caused by or complicated by an infection or another disease that resembles atopic dermatitis. 

Allergy testing in dogs typically takes one of two forms: intradermal skin testing or blood serum testing. Intradermal allergy testing is considered the gold standard for the diagnosis of atopic dermatitis and involves injecting small quantities of 40-60 different types of allergens into the dog’s skin, typically performed under general anesthesia by a veterinary dermatologist. A visible swelling will occur at the injection site if a dog has a reaction to the allergen, allowing determination of which allergens are triggering atopic dermatitis. Blood testing can be performed in a general veterinary practice; a blood sample is drawn from the dog and submitted to a testing laboratory. The lab searches for the presence of antibodies to allergens that are known to contribute to atopic dermatitis. The results of these tests can be used to formulate an allergen-specific immunotherapy based on the offending allergens. 

Management and treatment of mold allergies

The treatment of allergies, including those caused by molds, usually involves two steps: get control and keep control. This frequently requires using one or more therapies, often in combination with one another; these include, but are not limited to, corticosteroids, antihistamines, ATOPICA® (cyclosporine capsules), and Cytopoint® (Lokivetmab). 

Allergen immunotherapy, also known as desensitization or hyposensitization, consists of administering gradually increasing quantities and strengths of relevant allergens, either by subcutaneous injection or sublingual drops. The goal of this treatment is to help build tolerance to the allergens by tempering the immune response. This custom immune-therapy regimen can take up to 12 months before a response is observed. But the commitment may be well worth it as it may not only prevent the current allergies from worsening but also help prevent new allergies from developing.

Dogs suffering from allergies often develop secondary recurrent ear and skin infections. The inflamed skin can be susceptible to bacterial and yeast infections, which in themselves can lead to even more scratching. Targeted topical antimicrobial therapy shampoos and sprays containing chlorhexidine, miconazole, and/or ketoconazole may be recommended, as well as ear cleansers and treatments. In severe cases, oral systemic treatments with drugs such as ketoconazole, itraconazole, or terbinafine may be necessary.

Environmental therapy

Reducing the mold levels in your dog’s environment can help mitigate exposure and thereby reduce allergy symptoms. Unfortunately, because mold is all over, completely avoiding contact is not possible. Ideally, keep your dog (and his bed!) out of damp basements or garages; frequent baths or wipe-downs with a damp microfiber cloth can help remove mold spores that fall on his skin and coat. Inspect your dog’s favorite places, especially under his bedding. Large mold infestations in the home can usually be seen or smelled. If mold is present, these areas should be cleaned and treated appropriately. Depending on the location, extent, and type of mold, this may need to be done by a professional service. 

Because a mold allergy is environmental and environmental allergens are everywhere, complete alleviation of the condition is not usually possible and most dogs will require lifelong treatment.  But it can be successfully managed, resulting in a happier and more comfortable dog.

Photo: Przemysław Iciak/Getty Images

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Barbara Dobbins has been writing for WDJ since 2011 with a focus on veterinary and canine health topics. Her lifelong fascination with dogs has led her in many directions. As a youngster she would round up her dogs and horse for a day of adventure exploring and searching for buried treasure in the California hills. Inspired by Margaret Mead with a nod to Indiana Jones, she went on to study anthropology, archaeology, and museum studies and obtained a masters degree in art history. Then two new puppies bounced into her life, and Barbara launched into studying animal behavior and training and spent hundreds of hours volunteering in the behavior department at her local shelter. When her beloved Border Collie Daisy was diagnosed with a rare cancer, she dug deep to research all she could about the disease, and has written extensively about all sorts of canine cancer for Whole Dog Journal. Liaising between pet owners and veterinary practice, science, and research, she synthesizes these complex and data-driven subjects into accessible information. She continues to take inspiration from her two research assistants, mixed-breed Tico and Border Collie Parker.


  1. My dog has severe allergies to mold, fungus, mites & several other environmental allergens. We have him on a treatment regime like this and at first it was working well, but now not so much! He is having another bout of his bi- season allergic reaction which consists of him loosing hair in patches and breaking out in what looks like blisters, that start out as jump red bumps and eventually fill full of liquid and blood and then break open and turn to scabs. They are all usually around his collar… where it is impossible to keep them from breaking open! Especially since he needs to wear a collar or harness to go out for walks and stuff! This time they are not just between his shoulders but also under his neck near his chest and on top of him head too. He gets so tired and miserable when this happens! His vet and I are one our 3rd summer trying to find him a good treatment that will stop this from happening but no luck yet. He also gets these horrible ear issues too during these times. His ears get very full of fluids and wax even though I clean them almost everyday… then the fluid turns crusty and itchy as well!!

    • Poor dog, and poor you seeing him suffer. it may be worth trying traditional chinese medicine? i’ve heard it can work quite well for allergies. I dont have any experience myself but have been reading up on dog allergies and sounds like it would be worth a try 🙂

  2. My dog is the same Tiffany. We’ve tried everything apart from allergy testing which, my Vet says isn’t that reliable. We’re back to steroids and trying to keep the dose as low as possible. I try to get it to half a tab but her skin flares up. Our stable amount is 3/4 of a tablet a day. Obviously this is not good for her but there doesn’t seem to be any better option unless someone out there has anything.

    • Hi,
      CBD oil (or paste – Sativa) has worked well with our (blue, overbred) Staffy, who has a seasonal skin allergy – to grass!
      We rub paste onto his gums after a meal, with a frozen sprat as a treat afterwards. This has worked very well. On the rare occasions that there are any inflamed areas of skin (on tummy, inside of legs and paws) then we apply a CBD balm* and this quickly calms it all down.
      *Soothe, made by Herbal and also sold by CBD brothers, and which contains several other calming ingredients. I’m sure there must be something similar in the USA. I guess you could make up your own if you look at the ingredients list.

      I hope this helps someone 🙂

  3. Normally the immune system protects the dog against infection and disease, but with allergies, the immune response can actually be harmful to the body. Allergies may be thought of as an unnecessary normal immune response to a benign foreign substance. Unfortunately, allergies are quite common in dogs of all breeds and backgrounds. Most allergies appear after the pet is six months of age, with the majority of affected dogs over age one or two. And mold spores are common allergens.


  4. What about Apoquel? Our 18-month old Black Lab has responded well to Apoquel over the last month as did our Yellow Lab who passed away at age13. From what we were able to learn from our Vet and from the internet the risks are no greater with Apoquel than for the alternatives you mention.

  5. I will be watching the postings for ideas.

    I have a 8 year old Vizsla male (fixed) that has had blisters that develop between his toes. We think it is a grass mold issue. He is sensitive to where he steps in certain damp grass. He avoids it!

    After many visits to the veterinarian we have had very good success with a product supplement Zesty Paws Alter Immune Bites and have used it for about a year and a half.

    But this weekend after being out hunting his 3 of four of his paws have the moist, redness, and small blisters.

    Let me know of additional treatments. I have tryed Hydro cortazone spray )(over the counter for dogs) not much help, and diluted apple cider vinegar.

  6. Very informative! My dog is having some problems with stomach, gas and mostly paw licking. I suspect the dog park with years of wood chips may be culprit. Do you know if this could be it? I remember some children were allergic to something in wood chips in playgrounds .