I was on call last weekend and had two phone calls back-to-back about dogs being stung by jellyfish, so I thought I had better write something about that.

Both dogs had been stung, whilst walking on the beach, by a Portuguese man o’ war. There seem to have been a lot of these around this year and they can be quite nasty.

The Portuguese man o’ war, (Physalia physalis), is often called a jellyfish, but is actually a species of siphonophore, a group of animals that are closely related to jellyfish.

Resembling an 18th century Portuguese warship under full sail, the man o’ war is recognised by its balloon-like float, which may be blue, violet, or pink, and rises up to six inches above the waterline.

Lurking below the float are long strands of tentacles and polyps that grow to an average of 10 metres and may extend by as much as 30 metres. The tentacles contain stinging cells that deliver venom capable of paralysing and killing small fish and crustaceans. While the man o’ war’s sting is rarely deadly to people, it packs a painful punch and causes welts on exposed skin.

The good news is that dogs are much hairier than we are and that does offer them more protection from the stinging tentacles.

Dogs are curious creatures however, and the sight of something shiny, potentially a new toy, lying on the beach is often too tempting to resist. They will paw at them, bite at them and occasionally even swallow them, and the tentacles can give a nasty sting even if the creature is dead.

You should be on the lookout for these bizarre stinging creatures both in the shallow water and on the beach.

If your pet does get a sting they will show some rapid symptoms, which include pain, itching, licking the affected area, swelling, drooling, and vomiting. They will certainly be immediately distressed. The symptoms will usually subside within 15 to 20 minutes but can go on for longer.

If your dog is stung by a jellyfish stay calm, as this will help to keep your pet calm.

Pull any remaining tentacles off with a stick or towel, but never rub them or touch them with your hands. If you can, rinse your pet in salt water as this will help with the discomfort, but don’t rub sand into the affected area as this will irritate the skin further.

Seawater is better than fresh water for jelly stings. You should avoid applying vinegar or alcohol to the skin as this will make the pain worse.

You should always call your vet for advice as, in some instances, pain relief and anti-inflammatory medications are required.

So, keep an eye out for these beautiful but dangerous creatures and try to admire them from a safe distance.

• Lucy Richardson graduated from Edinburgh University in 2005. She started CedarTree Vets in August 2012 with her husband, Mark. They live at the practice with their two children, Ray and Stella, and their dog, two cats and two guinea pigs. Dr Lucy is also the FEI national head veterinarian for Bermuda