TL;DR: Swallowing a coin is a high-priority emergency for dogs because it can cause physical intestinal blockages or life-threatening zinc poisoning. Contact a veterinarian immediately to assess the risk based on the coin's size and metal composition.
What are the health risks if my dog swallows a coin?
When a dog or puppy swallows a coin, it is classified as a foreign body ingestion. Unlike food, coins are indigestible and pose several risks to your pet's health:
- Physical blockages in the digestive tract.
- Chemical poisoning from the metals used to mint the currency.
Is it a medical emergency if my dog eats a coin?
Urgency Level: High. You should contact a veterinarian or an emergency animal hospital immediately because while some coins may pass, others cause life-threatening issues:
- Pennies minted in the U.S. after 1982 are made primarily of zinc, which is highly toxic.
- Stomach acid breaks down the coin, allowing zinc to be absorbed into the bloodstream.
- Zinc absorption causes rapid destruction of red blood cells (hemolytic anemia) and kidney failure.
How does taking a photo of a duplicate coin help with my dog's triage?
Providing visual context helps your medical team determine the exact level of risk:
- Find a duplicate of the coin your dog swallowed and take a photo next to a common object for scale, such as a paperclip or a key.
- A photo helps the vet identify the size and material of the object to determine if it is large enough to cause a physical bowel obstruction.
- Knowing the exact denomination helps the medical team determine if there is a specific risk of heavy metal toxicity.
Clinical Context (Merck Veterinary Manual)
Ingestion of alkaline batteries presents a risk of gastrointestinal tract corrosive injury and foreign body obstruction, most commonly seen in dogs. Alkaline gel causes liquefactive necrosis of tissues on contact, resulting in burns that can penetrate deeply. Lithium disk batteries may lodge in the esophagus and generate a current against the esophageal walls, resulting in circular ulcers that have the potential to perforate. Radiographs may help confirm the diagnosis and location, although some disk batteries do not show up well. For intact batteries, induction of emesis may result in expulsion unless the battery casing is punctured due to the risk of alkaline gel leakage. When disk batteries have been ingested, 20 mL boluses of tap water every 15 minutes will decrease the severity and delay current-induced esophageal ulceration. Batteries that do not pass through the pylorus within 48 hours of ingestion may require surgical or endoscopic removal. Batteries that have obviously been punctured should be removed surgically to prevent gastric or intestinal ulceration. Serial radiography to verify battery location is recommended until the battery is expelled.
Chapter: Toxicology, Emergency
Source: The Merck Veterinary Manual, 11th Edition (Page 3003)