Portuguese Man O’ War

Following recent media coverage of large numbers of Portuguese Man O’ War washing up on the Cornish coast the SLSGB Clinical Advisory Group have issued the following bulletin to help understand why the risk is so high and how to treat if stung.

What is Portuguese Man O’ War and why are they so dangerous?

  • Portuguese Man O’ War or Physaliidae is closely related to a jellyfish and consists of a floating colony of hydrozoans – lots of really tiny marine organisms living together and behaving collectively as one animal.
  • It’s the tentacle-like polyps that can give an agonising and potentially lethal sting. These can cause cardiovascular, respiratory and neurological symptoms; on rare occasions its sting can kill.
  • Stings cause severe pain to humans and leave bright red whip-like welts on the skin for days afterwards.
  • A stranded Portuguese Man O’ War looks a bit like a deflating purple balloon with blue ribbons attached
  • If you see one, do not touch it or pick it up.


If Portuguese Men ‘O War are present on your beach you need to factor this in to your  Risk Assessment before any training , coaching or events take place considering the following factors;

The rationale for this is the risk of worst case scenario. That being a life threatening medical complication, following a sting that requires immediate extraction to hospital.  The risk assessment should be carried out if clubs wish to either do local training or patrolling and it should cover information on wind and tide state.  It is recommended for those clubs (while the threat of Man O’ War exists) that have inshore rescue boats can enhance the risk assessment by going on to the water to assess the risk further out to sea.

  1. High risk factors: the number of people potentially exposed to more than 2 or 3 man of war in the water; first aid treatment available; and remoteness of the beach to a hospital. 
  • E.g. If there are more than 3 in your area this is deemed unsafe for in water activity
  • Anything less than 3 consider PARQ’s to be completed and note anybody with a significant medical history, particularly a history of allergies. The latter are potentially at higher risk of complications if stung.
  1. A qualified Surf Lifeguard or SLSGB First Responder with a full response kit to include O2 therapy.
  2. That your beach has easy access for emergency response.

CONSIDER: Do you need to go into the water at this specific location, is there somewhere safer and not to put people at avoidable risk?

Treatment in the event of a Sting

The following guidance is based on the ILSF medical position statement and a recent review article, which can be found by following the links at the bottom of the page.

Safety ⇒ “ABC” assessment ⇒ then focus on “jellyfish” sting:

  1. Prevent further discharge of nematocysts
  2. Alleviate local effects of venom
  3. Control systemic reactions, including shock.


  1. Prevent further discharge of nematocysts

               – Remove tentacles, (gloves may be preferable to prevent additional stings), irrigate with sea-water (fresh water will worsen the sting sensation/ nematocyst load) to assist removal. Wash hands as soon as possible afterwards.

               – Even dehydrated “jellyfish” on the beach can sting. Handle with care 

               – Wetsuits/ PPE will reduce the incidence of stings.

  1. Alleviate local effects of venom

               – Hot (not scalding!!) water (approx. 45 deg Centigrade) has subtly better evidence than cold packs for pain relief. Either would reduce pain. In addition advising patients to visit a pharmacist and follow their advice for analgesia, in context of their medical conditions. E.g. Paracetamol and Ibuprofen.

  1. Control systemic reactions, including shock.

– Systematic assessment and treatment of “ABC’s” including oxygen. Hospital is required if there are any treatments required resulting from the “ABC” assessment. Including any anaphylaxis.

– If pain remains the same or worsening after 20minutes of treatment – hospital admission required.

               – The default position is a trip to the Emergency Department if any concerns.

Further reading

MPS- 05 2015 Envenomation: http://www.ilsf.org/about/position-statements
Journal review: http://www.mdpi.com/1660-3397/11/2/523/htm

Image provided by –  https://oceanservice.noaa.gov/facts/portuguese-man-o-war.html