The relationship between the eucalyptus plant and animals with allergies is complex. In some cases, animals are allergic to either the pollen or the oil of the plant, causing inflammation and itching of the skin along with possible respiratory symptoms such as coughing, sneezing, and shortness of breath. In other cases, eucalyptus is often successfully used to counteract both the inflammation of the skin as well as respiratory signs such as coughing in allergies to other substances. Although eucalyptus can be used topically, caution should be taken to ensure the patient doesn’t ingest the product as the oil from the eucalyptus is a neurotoxin and can cause neurological symptoms such as depression, confusion, and seizures.

Eucalyptus oil can be used to help ease the symptoms of allergy, but it also has the potential to cause allergies, and can be dangerously toxic when ingested.

Symptoms of seasonal allergy: 

Symptoms of eucalyptus poisoning:

Eucalyptus extract is used in many therapeutic preparations for its anti-inflammatory properties as well as its ability to relieve chest congestion. Eucalyptus is often used as an ingredient in shampoos and other natural treatments both for humans and for canines. The compounds in eucalyptus are well known for their ability to repel fleas. In concentrated doses this oil is quite toxic to your pet, however, the eucalyptus oil that is contained in commercial pet products is significantly diluted making it safe to use as instructed. Eucalyptus is also used as a topical antiseptic and antibiotic and may be helpful in the area of pain relief.

Eucalyptus can help soothe some of the symptoms of allergies and it is also helpful in warding off fleas as well. Unfortunately, there can be a dark side to this plant, and sometimes it can cause a contact allergy to the oil it develops. Ingesting too much of the oil from licking it off the fur can also lead to serious trouble, especially if the oil is undiluted. Ingestion of large amounts of eucalyptus oil can result in both neurological and gastrointestinal damage. The pollen from the eucalyptus tree is allergenic, but its low severity makes reactions to the allergen fairly mild.

If your pet is showing signs of a seasonal allergy to the Eucalyptus himself, the condition of the skin will prompt your veterinarian to get a sample of the skin for cutaneous cytology. General tests to rule out disorders like chronic bacterial illness, hypothyroidism, or blood chemistry imbalances will also be done at this point. Cutaneous cytology is the microscopic examination of the skin cells and the organisms found on or around them. This technique can be used to identify biological organisms that might be detrimental to your pet such as mites, fungi, or bacterial infections. The results of this test, combined with the seasonality of the symptoms, will suggest a preliminary diagnosis of seasonal allergy.

Due to the astringent nature of the eucalyptus oil, it is not recommended that vomiting be induced in the event of an overdose, as this can cause further damage to the throat and lungs. If any oil is still remaining on the skin, the area should be thoroughly flushed with water to avoid further adverse skin reactions. The veterinary hospital is likely to start treatment with a gastric decontamination, followed by the use of activated charcoal which is used to soak up any remaining toxin in the stomach. In the case of eucalyptus oil ingestion, it is critical that the gastric decontamination is done under general anesthesia, and there is a risk of exposure of the windpipe and lungs to the eucalyptus oil.

 Seasonal allergies in dogs have the tendency to worsen with time, eventually causing your pet to show signs of allergy year-round. Antihistamines are only effective for twenty to thirty percent of our canine companions initially, and even those individuals often develop a tolerance for them, causing their effectiveness to fade. Corticosteroid medications are usually effective at reducing allergy signs but have also been known to cause serious side effects. Immunotherapy is another option for patients that are affected by unavoidable allergens. Once an intradermal test is completed to verify which allergens are causing the reactions, a personalized injection is prepared. This customized formula is injected into the patient either weekly or monthly, which desensitizes them to the allergen. This method of treatment is time consuming and expensive, however, it has a very high success rate, especially in younger dogs.

Due to the poisonous nature of the oil, it is important to follow all guidelines listed when using products that include this oil. Used incorrectly, this oil can cause further irritation rather that helping correct the situation.  Used correctly, it can contribute to improving the prognosis and comfort for animals plagued by uncomfortable allergy symptoms. It is important to consult your veterinarian before starting any treatment plan, especially treatment plans that include the use of essential oils. This will allow for testing to confirm the preliminary diagnosis, and you can check to ensure that the eucalyptus is not an active allergen for your pet as well.