The summer is a great time for swimming – and, luckily, there’s an evidence-based systematic review of treatment of jellyfish stings available from Annals of Emergency Medicine. Unfortunately, it’s only the relatively benign and inconvenient species from North America, rather than the life-threatening species found more commonly in the southern hemisphere.
Literally, everything has been tried on jellyfish stings in an attempted in treatment, from vinegar, to ammonia, to ethanol, to meat tenderizer, to magnesium chloride, and the list goes on. Essentially, the attempted treatments fall into two camps – wash off the nematocysts without inducing discharge, or simply to treat the pain and tissue damage from the venom itself.
The American Red Cross First Aid consensus suggests the use of vinegar – which, according to this review, induces nematocyst discharge in everything but some Physalia species. The real answer is…no single agent reliably inactivates nematocysts from every organism. The authors recommend simply using readily available saltwater to wash the affected area. For post-envenomation pain, topical anesthetics such as lidocaine and hot water were found to be most reliably effective. Given the limited availability of anesthetics to laypersons, the best treatment is likely to be hot water submersion to help inactivate the toxins.
“Evidence-Based Treatment of Jellyfish Stings in North America and Hawaii”
www.ncbi.nlm.nih.gov/pubmed/22677532