Jellyfish are a type of boneless sea creature with a bell-like body and long tentacles. The tentacles of jellyfish have nematocysts, which are the cells that cause the stinging sensation. Although the fur on most dogs offers a layer of protection, they can be just as vulnerable to stings on lightly furred areas such as the face, feet, and abdomen. They are also at risk for stings inside their mouths if they attempt to pick up a jellyfish with their mouths, especially as this stinging action can occur several weeks after the death of the jellyfish.

The sting of a jellyfish can cause great discomfort to both humans and animals alike. Encountering a jellyfish on the shoreside may warrant a veterinary clinic visit if your dog’s reaction to the sting becomes intense.

There are many types of jellyfish in the ocean, and they have developed several different types of toxins. Common symptoms of stings by the jellyfish include:

There are some types of jellyfish that have more dangerous stings than average. Some of the most dangerous are: 

Lion’s mane - The largest of the jellyfish, this monster can span up to 8 feet across its bell and has tentacles that can trail over 100 feet behind them. The toxin from the Lion’s Mane jellyfish can cause serious muscle cramps and potentially deadly breathing problems.

Irukandji jellyfish - This tiny jellyfish is only 5 millimeters across with three-foot long tentacles that contain one of the most potent toxins on earth, causing severe pain in the back and kidneys, burning sensations of the face, and agonizing muscle pain. This sting can be fatal without treatment. 

Box jellyfish - Also known as the sea wasp, this jellyfish has enough toxin to kill around 60 adult humans. It is a fast acting toxin that causes intense pain. The pain itself is powerful enough to cause shock or heart failure, and the toxin that is injected attacks the heart, nervous system, and skin cells. Those that survive the sting of the box jellyfish report pain that continues for weeks and often retain permanent whip like scars.

Your dog may come across jellyfish if he is allowed to play in the surf or when walking on the beach. Dead jellyfish often wash up on shore and dogs can encounter them and may try and explore them either by sniffing or mouthing the body. The stingers on the jellyfish can continue reacting for several weeks after the jellyfish itself dies.

The diagnosis is generally going to be made based on symptomatology, combined with actions that may have allowed your canine to have contact with a jellyfish. Finding out what sort of jellyfish stung your pet can be helpful in determining what the course of action should be for treatment. If the contact is made with a dead jellyfish, then bringing the remains into the clinic may help with determining which jellyfish stung your pet. It is important  that you not touch any part of the jellyfish with your bare hand to avoid triggering more of the specialized stinging cells.

If your dog is stung by a jellyfish, the primary concern is to remove any stingers and stop the chemical reactions. Soaking the area in seawater, vinegar, meat tenderizer, or a 70% alcohol solution will prevent the tentacles from releasing any more toxins. It is imperative to avoid using fresh water as fresh water can activate the cells rather than preventing them from being triggered. You can remove any further jellyfish remains by applying sticky tape to your animal’s skin where the tentacle was located, then lifting the tape off your dog, and the remains with it. Once the remains have been removed, it is a good idea to contact your veterinarian anytime that your pet is stung by a jellyfish, however, if the following symptoms occur, you should take your pet directly to the veterinary clinic:

In some cases, antihistamines will be recommended to reduce any allergy related swelling and prevent further skin damage.

Using beaches that are monitored will help to avoid contact with jellyfish as they often have signs or warning flags if there are a proliferation of jellyfish either in the water or on the beach. Jellyfish also tend to range nearer the shore during high winds and may appear in large groups under these conditions. If you or your pet encounter a jellyfish on the beach, do not touch it, or allow your pet to touch it, and let a lifeguard or other beach authority know so they can safely remove the body. You can also help to protect your dog’s skin when swimming in the ocean or walking on the beach by applying petroleum jelly to any exposed skin, such as the nose leather, abdomen, eye rims, and footpads. Remember that unfixed males should also have their testicles protected from the stinging cells.