Dr. Tina Wismer is the medical director of the ASPCA Animal Poison
Control Center in Urbana, Illinois. She is board certified by both the American Board of Toxicology
and American Board
of Veterinary Toxicology.
If your dog eats a mushroom bought
at the grocery store, there is little risk of poisoning. Most mushrooms that
are safe for people are also safe for pets. Wild mushrooms, unfortunately, may
be deadly. And in the fall and spring, they can be a concern in many parts of
the country. Dogs are more frequently affected by mushroom poisoning due to their scavenging while in the yard or on walks, but cats can be affected, too. In
general, you should consult your veterinarian immediately if you suspect
mushroom ingestion — and get a sample of the fungus if you are able.
Mushrooms Are Everywhere
Mushrooms of many different species are found in parks, yards and woods. Wild mushrooms range from edible
varieties to those that cause vomiting and/or hallucinations — or even liver failure and death — in
people and pets. Mushroom identification is very difficult, and you should consult a trained professional before eating a wild
mushroom of any kind. Mushroom types vary around the country,
and the appropriate departments of colleges, schools or agricultural
extension offices should be consulted when attempting to identify mushrooms, as
their prevalence, preferred locations, suspected toxicity and even physical appearance
can differ by region.
To make things even more difficult, the mushroom your dog eats may not be the same as the one still
on the lawn. Many varieties grow in the same conditions, and dogs may
ingest one type but leave another in the same location untouched, thus leading
to a false assumption about what variety was eaten. In addition, many
mushrooms, especially those found everywhere and commonly called
"little brown mushrooms," can look similar yet cause different symptoms that ultimately may be lethal.
Despite their outward appearances,
mushrooms are typically grouped by toxicologists and mycologists (those who
study mushrooms) according to the dominant suspected toxin they contain
(although many poisonous mushrooms may contain more than one toxic substance).
Many mushrooms are also known by their common names, but since these can vary by
country, region or culture, the same mushroom can be called several things. Here is a brief
overview, based on calls to the ASPCA’s poison control hotline, of some of the
more common mushrooms that cause problems in pets. See our companion
photo gallery for a look at some of the more recognizable species of
potentially poisonous mushrooms found in North America.
Pretty but Poisonous
Thankfully, many
mushroom species cause only gastrointestinal upset. Depending on the species,
affected dogs begin to vomit within 15 minutes to several hours after ingestion; the
vomiting can last a few hours to a couple of days.
Muscarinic mushrooms (Inocybe and Clitocybe species)
stimulate salivation, urination, diarrhea
and vomiting. The onset of signs is quick, usually within five to 30
minutes. Signs can persist for several hours if untreated, but are resolved quickly with administration of atropine, a common treatment for certain
kinds of poisonings, by your veterinarian.
Isoxazole mushrooms (Amanita gemmata [gemmed
mushroom], Amanita muscaria [fly agaric, woodpecker of Mars],
Amanita pantherina [panther or panther cap mushroom], Amanita
smithiana, Amanita strobiliformis and Tricholoma muscarium) have
fluctuating signs of excitation and depression, which often appear soon
after ingestion. Some of the common names or nicknames of mushrooms, such
as fly agaric or woodpecker of Mars, are based on uses in folklore or
fanciful oral history. For example, in some cultures poisonous mushrooms were set out to soak in milk or water because they were thought
to kill flies, such as the case with fly agaric (the traditional red and white toadstool). Animals who ingest these
mushrooms may initially vomit but then become intoxicated. Care must be
taken when treating the agitated stage, as some patients will stop
breathing after the administration of a sedative. Signs occur quickly (30
minutes to two hours) after ingestion and can last for eight to 24 hours or
longer. Affected animals typically recover, but a veterinarian should be
consulted.
Bad Magic
The next order of
mushrooms of concern include the following:
Psilocybin [Psilocybin cubensis
(hallucinogenic or magic mushrooms)] can cause agitation, hallucinations,
drunkenness and fever in dogs. These mushrooms stimulate neurotransmitters in the
brain. Signs occur quickly (within 30 minutes to three hours) and can last up to three days.Poisoned animals sometimes injure themselves
due to agitated behavior.
Gyromitrin-containing mushrooms, such astheGyromitra species (commonly called false
morels because they look like edible morel mushrooms), as well
as Helvella crispa and H. lacunosa (elf’s saddle)contain compounds related to
rocket fuel. When ingested, these mushrooms can cause vomiting and seizures.
Animals who eat one need to see the veterinarian, as fever and kidney and liver
failure can develop within six to 12 hours or sooner. Prognosis is guarded
in patients developing signs beyond gastrointestinal upset.
Deadly Fungi
The deadliest mushrooms can give you a false sense of security.
Amanitins, and to a lesser degree phalloidins, are liver toxins found in Amanita (death cap and destroying angel complex), Galerina (autumn galerina)and Lepiota
(deadly parasol or deadly lepiota)mushrooms.
Animals ingesting amanitins have a lag period of six to 12 hours before they
start experiencing vomiting, diarrhea, abdominal pain, dehydration and lethargy.
These animals appear to recover, but in three to seven days, liver failure, along with seizures and bleeding either internally or out
of body orifices, can occur. Most animals do not survive. Many people who
are poisoned by these types of mushrooms require liver transplants. In pets, where this is typically not an option, such
poisonings are generally fatal.
So What Should You Do?
If you suspect that your pet has eaten
a mushroom, call your veterinarian right away. He or she may want to make your
pet vomit or give a dose of activated charcoal to bind the toxins or provide
other supportive care, such as fluids or gastrointestinal protectants. Attempting
to get the mushrooms identified can help determine if any additional treatments
are needed, but do not delay initial contact with a veterinarian in order to
attempt identification. The North
American Mycological Association (NAMA), which tracks mushroom poisonings
in pets and people, advises attempting to obtain a sample of the suspected
mushroom and placing it in a paper or wax paper bag (not plastic) and
refrigerating it until an expert can examine it. NAMA also advises writing down
where you found the mushroom, as sometimes location helps in identification.
Location can also help determine whether the mushroom was the cause of a poisoning or
if pesticides played a role. As a preventive
step, if you notice mushrooms growing on lawns or in mulched areas, remove them. The best prevention is to keep your pets away from all
wild mushrooms.
