False Queen Anne's Lace Poisoning in Cats

False Queen Anne’s lace is a member of the Apiacea family and is known throughout the world by its scientific name; Ammi majus. False Queen Anne’s lace is also known by its common names such as; lace flower, Queen Anne’s lace, lady’s lace, greater ammi, bullwort, false bishop’s weed, bishop’s weed and the bishop’s flower. This common ornamental plant was first introduced from Asia and has spread throughout the US southern coastal regions. The false Queen Anne’s lace plant can be identified by its 1-2 foot long stem and distinctive lace-like flower clusters that are white in coloration. 

False Queen Anne’s Lace poisoning in cats is a type of plant-sourced toxicity caused by the ingestion of any part, but especially the seeds, of the false Queen Anne’s lace plant. The toxic components of the false Queen Anne’s lace plant are primarily furanocoumarins and nitrates. Upon ingestion, these toxic elements cause photosensitization to the feline, or exudative and ulcerative dermatitis. There is no specific antidote for a false Queen Annes lace poisoning in cats, but the veterinarian can provide general toxicity treatments that can save your cat’s life. 

Ingestion of the false Queen Anne’s lace plant will cause a feline to develop photosensitization. The clinical condition known as photosensitization is characterized by hyperactive sensitivity to sunlight on unprotected skin. The areas of the cat’s body that are not protected by fur will blister, wrinkle, split open or slough away when exposed to sunlight due to the plant’s photodynamic agents. The open skin sores pose a threat to secondary infections, which can be identified by pus-filled locations and a high fever. False Queen Anne’s lace also affects the feline’s eyes, causing conjunctivokeratitis and clouding of the corneas. The effects this plant has on a cat’s eyes can cause permanent scarring, which can leave the feline blind. 

False Queen Anne’s lace poisoning in cats is caused by the ingestion of any portion of the false Queen Anne’s lace plant, but the seeds of the plant are known to contain the highest level of toxicity. The toxic components of the plant are primarily furanocoumarins toxins; xanthotoxin, bergapten, as well as Methoxypsoralen 8 and 5.  The false Queen Anne’s lace plant also contains nitrates that are known to cause photosensitization in felines in addition to other domestic and livestock animals.

Diagnosing a false Queen Anne’s lace poisoning in cats is difficult if the cat owner did not see the ingestion of the toxic element take place. There is no specific test available for identifying false Queen Anne’s lace poisoning in felines, so your veterinarian’s diagnosis will be based on ruling out other possible causes of your feline’s current symptoms. The diagnostic process will begin with a physical examination, review of the feline’s medical history and a consultation with the pet owner. It will be important for you to inform the veterinarian about your feline’s recent actions and exposure to false Queen Anne’s lace, as this information will aid in ruling out other possible causes. The clinical signs that false Queen Anne’s lace poisoning in cats causes mimic other feline related health conditions. The veterinarian will want to conduct a series of diagnostic tests to ensure your cat is truly suffering from a false Queen Anne’s lace toxicity and not a more severe underlying condition. Diagnostic tests the veterinarian will likely request to be performed on the feline include: 

• CBC Complete blood cell count 
• Biochemical profile (blood work) 
• Blood smear test 
• Urinalysis (examination of urine) 
• Fecal floatation test
• Fecal examination 
• Skin scraping test
• Skin biopsy 

False Queen Anne’s lace intoxication has no specific antidote, but treatment is available from a licensed veterinarian. The veterinarian may administer medication to induce vomiting or give the feline an activated charcoal solution to bind with the toxic plant chemical, to later be passed in fecal form from the body.  

To further eliminate the false Queen Anne’s lace toxins, the veterinarian will likely start your cat on fluids given intravenously to replenish lost fluids and aid in elimination. As the photosensitivity continues, the feline will need to be kept out of sunlight to prevent the rays from triggering an ulcerative dermatitis response. In order to treat the feline’s current skin conditions, the doctor may administer a corticosteroid or antibiotic to attend to secondary infections. 

The prognosis for false Queen Anne’s lace poisoning in cats is positive if said feline has received medical treatment. The majority of the treated felines will begin to recover within a few days to weeks, but permanent scar tissue of the skin and eyes is a likely expectation.