Lemon and Lime Poisoning in Dogs

The fruits of the lemon and lime trees are well-known additions to food and drink in the human world but can be a danger to our pets. Lemons and limes, like other citrus fruits, contain the essential oils limonene and linalool, as well as a phototoxic compound known as psoralens. Although a small amount is unlikely to pose a serious threat, it can cause gastrointestinal upset. Ingestion of larger quantities of these fruits, or the trees that they grow on, can cause more serious distress, though this is uncommon as dogs do not find these fruits palatable.

Both lemon (citrus limon) and lime (citrus aurantifolia) trees produce phototoxic compounds called psoralens as well as linalool and limonene. Although safe for humans, these substances are potentially toxic to canines in large amounts.

Symptoms of poisoning from citrus fruits like lemons and limes are caused by a combination of the phototoxic compounds known as psoralens and the essential oils limonene and linalool.

• Cold limbs
• Collapse
• Depression
• Diarrhea
  
• Excessive drooling
  
• Lethargy
  
• Liver failure
• Loss of coordination
  
• Low blood pressure
• Photosensitivity 
• Rash or skin irritation
• Sudden death
• Tremors
• Vomiting
• Weakness
  

Types 

Both psoralens and linalool are found in other plants as well. However the essential oil limonene is generally restricted to citrus plants. Other plants that produce linalool include:

• Beech trees 
• Cinnamon
• Laurels
• Mint plants
• Rosewood

Other plants with high concentrations of psoralens:

• Anise seeds
• Caraway seeds
• Carrots
• Celeriac
• Celery
• Chervil
• Cilantro
• Coriander seeds
• Cumin seeds
• Dill
• Fennel seeds
• Figs
• Grapefruit
• Lovage
• Mustard seeds
• Oranges
• Parsley
• Parsnips
• Root parsley

The toxicity of citrus plants lies in the essential oils limonene and linalool, as well as in the phototoxic compound psoralen.

Limonene 

A terpene produced in all citrus fruits which is the main component in the aroma of the different citrus fruits. It is often used in cosmetic products, flavoring compounds, and cleaning products. D-limonene is often employed in fragrances and shampoos for dogs. It is important to note that although the amount of d-limonene in these shampoos is safe for most canines, can be lethal to use on cats. 

Linalool

A terpene that contributes a floral scent to the citrus aroma, linalool is often utilized as an insecticide in soaps and lotions as a fragrance.

Psoralen

A compound found in many plants, including citrus plants like lemons and limes, it is used as a treatment for skin disorders but can also induce phototoxicity.

If you catch your pet consuming any type of citrus plant, signs and symptoms combined with the identification of the plant may be sufficient to make an initial diagnosis. Your veterinarian will question you regarding factors that will help to choose the most effective treatment plan, such as the amount of plant material ingested, how long ago it was ingested, and what part of the plant was eaten. If the toxin is unknown because the ingestion was unwitnessed, a urinalysis, blood chemistry profile, and complete blood count will be needed in order to determine which toxin is causing the distress. 

Any skin interaction will be noted, and any vomit or stools will be analyzed for toxins as well. Neurological testing to measure your pet’s reflexes and coordination may also occur during the diagnostic appointment. These evaluations are done in an attempt to pinpoint the specific areas of the nervous system that have been affected.

Any parts of the skin that have been exposed to the oil of the citrus plant should be washed immediately removed using a mild soap and clean water. Limonene and linalool are included in several dog shampoos as a fragrance and therefore, should be avoided when removing citrus oil. It is not always advised to induce vomiting as breathing the oil into the lungs can be harmful. Gastric irrigation will be performed on the patient to physically remove as much of the toxin from the digestive system as possible. Activated charcoal will then be administered to prevent any further absorption of the toxic compound into the bloodstream. 

There is no antidote for either the psoralens or the essential oils, so treatment is generally supportive beyond decontamination. This can include IV fluids for dehydration as well as mixtures of electrolytes and sugars to adjust for any imbalances that might develop. If your dog is having difficulty breathing, oxygen will be provided, and antiseizure medications may be administered if tremors become acute.

Prognosis is typically good as the poisoning symptoms only last a few hours, however, ingestion of essential oils including lemons and limes can have a more dire outcome.  Dogs that require gastric lavage and are recovering from anesthesia may have coordination difficulties and confusion until the sedatives have fully cleared the patient’s system. 

Cases of phototoxicity have developed with citrus poisoning, and your pet should be sheltered from sunlight for around 48 hours after treatment to prevent skin reactions. Your veterinarian will most likely recommend regular monitoring of blood chemistry levels for your pet after any type of poisoning, particularly in relation to liver and kidney functionality or impairment.

Lemon and lime poisoning can be expensive to treat. If you're worried about your ingesting citrus, start searching for pet insurance today. Brought to you by Pet Insurer, Wag! Wellness lets pet parents compare insurance plans from leading companies like PetPlan and Embrace. Find the “pawfect” plan for your pet in just a few clicks!