Mushroom Poisoning in Dogs

Siberian Husky resting close by the deadly Amanita muscaria mushroom

Pets can get themselves into all sorts of trouble outside, but beware of the hidden dangers in wild mushrooms! All wild-growing mushrooms should be regarded as toxic until proven otherwise. There are no wild mushrooms that can be eaten raw by us humans, and cooking them is essential even if it is considered an ‘edible’ mushroom.

Identifying mushroom species is often complicated. Mushroom identification often requires a consultation with a poison information center that has experience in identification, or a consultation with a mycologist (a person that studies the branch of biology focusing on the study of fungi). Like humans, toxicity in dogs often depends on how much was eaten, as well as the type of mushroom eaten.

Erring on the side of caution and safety, if your dog has eaten wild mushrooms they should be seen by a veterinarian immediately for ‘decontamination’ (making them vomit or pumping their stomach to remove the contents). Vomiting the fungi is important, and often is followed up with an activated charcoal treatment and fluid therapy to help flush out the toxins. If your dog becomes ill, and you suspect mushroom ingestion, place any vomit and/or bowel movements – and any mushrooms you feel your pet may have eaten – in a plastic bag for identification by your veterinarian. Your veterinarian may need to sedate your pet in order to treat them, due to the altered behaviors your dog may be exhibiting that’s attributed to mushroom ingestion.

There are 8 groups of toxic mushrooms (see Table 1 at the end of this article showing these toxic mushrooms and their specific toxin). The Amanita, Galerina, and Lepiota species are the most toxic and dangerous of the mushroom species, as they contain cyclopeptides. Amanita species is the most common cause of fatal mushroom poisoning in dogs as they are severely toxic. Amanita also is responsible for 95% of mushroom related deaths in people. The Amanita phalloides (Image 1), the Death Cap Mushroom, is responsible for more than 50% of all mushroom associated deaths in people, and most of the reported fatal cases in dogs. It’s a true emergency if you or your pet has eaten this species of mushroom-seek medical attention immediately!

Toxic cyclopeptides in this mushroom species are rapidly absorbed from the stomach. There are distinct symptoms of cyclopeptide poisoning that occur 10-12 hours after being consumed. Most symptoms only occur when there are apparent liver and kidney complications after the destruction of cells has already begun. Other symptoms that may occur include bloody diarrhea (gastroenteritis), vomiting, nausea, abdominal pain, dehydration, electrolyte imbalance, fever, fast irregular heartbeats (tachycardia), high blood sugar (hyperglycemia), yellowing of the skin (jaundice), uncoordinated movements, excessive drooling, seizures, and coma.

In Wisconsin, the Amanita species is very commonly found in conifer areas (trees with needle leaves like pines). It is a mushroom that is often mistaken with a delicious and edible mushroom called Boletus edulis, which can be found in the same habitat at the same time where Amanita is also available. The Amanita muscaria (Fly Amanita) is very common in Wisconsin and often times wild animals, such as squirrels, will be eating the Amanita species but this does not make it safe for us to eat by any means. Reports from northern climate areas state that even caribou seek out and eat Amanita muscaria for its euphoric effects.

Boxer resting next to the edible Boletus edulis mushroom

Preventing exposure is the best method of controlling mushroom poisoning. Keeping your dog leashed and close to you when out and about in nature is a good way to keep your pet safe from accidental ingestion. Removing any wild mushrooms from the yard can also help; just make sure you don’t pick and put them in a spot your pet can get into. Always wash your hands after touching wild mushrooms. Much like seeds blowing in the wind when a dandelion is bumped, mushrooms have very small spores that are spread the same way. Spreading of spores is how mushrooms reproduce; some spores are so small you won’t even see them.

Picking wild mushrooms to eat should only be for those knowledgeable about mushroom identification. There are many poisonous look-alikes to the commonly known edible species and it’s way too easy to mistake a harmless mushroom for a poisonous one.

With treatment by your veterinarian the outcome of your pet eating wild mushrooms is typically good, especially if caught quickly. Being aware of the many hidden dangers out there in nature – such as wild mushrooms – can help you keep your pets safe. Education is key and will also help you know what to do in the event of an emergency poisoning situation.