Does Your Dog Have a Mold Allergy?

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.

Diagnosis

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