Effective Treatments for Jellyfish Stings

The purpose of the study is to attempt to determine which treatment from commonly used treatments is the best at reducing pain and redness of the skin after a sting from a Portuguese Man of War, Chrysaora chinensis, or Chrysaora fuscescens. Jellyfish stings are a common occurrence in many parts of the world causing significant morbidity to persons stung by jellyfish while participating in marine activities whether commercial or recreational. Much debate and confusion exist both in the medical literature and the common recommendations regarding how to treat persons stung by jellyfish. Specifically concerning what topical treatments are most efficacious at decreasing envenomation by nematocyst on skin, preventing the firing of un-discharged nematocyst, decreasing inflammation and pain resulting from envenomation by nematocyst. Antidotal recommendations and past studies have referenced numerous different topical treatments for jellyfish stings including but not limited to vinegar, urine, alcohol, distilled spirits, ammonia, bleach, acetone, bicarbonate slurry, lidocaine, meat tenderizer, Coca Cola, old wine, salt water, cold packs, hot water, and commercial products such as Stingose and Stingaid. Conflicting data exists regarding what works and what does not for nematocysts discharge, skin erythema, and pain reaction. The investigators would like to investigate which treatment is best out of some of the more commonly studied treatments for reducing pain and erythema. The investigators would like to complete a research study to try to bring some reasonable evidence to the field treatment of jellyfish stings, namely, the decontamination process (e.g., what can you put on a jellyfish sting that will be helpful, based on real data?). The questions asked are as follows: What topical treatments for jellyfish stings actually decrease the amount of inflammation seen on a macroscopic level on the skin of humans? What topical treatments for jellyfish stings actually decrease the sensation of pain in humans? Do topical chemical treatments cause different outcomes when exposed to the above parameters? Do different species of jellyfish nematocysts react differently based on the type of topical chemical treatment used? What is the variation of effects of topical treatments based on the species of jellyfish sting? Specifically, the investigators will be stinging human subject on both arms with a segment of tentacle for approximately 2 minutes. This will be followed by no treatment on one arm (control arm) and by treatment on the other arm with either: acetic acid (5%), sodium bicarbonate slurry (50%), papain slurry (70%), ammonia (10%), viscous lidocaine (4%), isopropyl alcohol (70%), or hot tap water (40 degrees Celsius). Outcomes measured will include pain and erythema.

Acetic Acid (5%) Dosage form: Liquid Dosage: 5 ml topical Frequency: every 2 minutes Duration: 30 minutes

Sodium Bicarbonate Slurry (50%) Dosage form: Liquid slurry Dosage: 5 ml topical Frequency: every 2 minutes Duration: 30 minutes

Papain Slurry (70%) Dosage form: Liquid slurry Dosage: 5 ml topical Frequency: every 2 minutes Duration: 30 minutes

Ammonia (10%) Dosage form: Liquid Dosage: 5 ml topical Frequency: every 2 minutes Duration: 30 minutes

Lidocaine (4%) Dosage form: Liquid Dosage: 5 ml topical Frequency: every 2 minutes Duration: 30 minutes

Isopropyl Alcohol (70%) Dosage form: Liquid Dosage: 5 ml topical Frequency: every 2 minutes Duration: 30 minutes

Hot Tap Water (40 degrees Celsius) Dosage form: Liquid Dosage: 5 ml topical Frequency: every 2 minutes Duration: 30 minutes

Mean Change in Pain in the Treated Human Arm (Not Placebo) From Baseline Determined by Measures (17) Taken Over 24 Hours

Pain is measured on a scale of 1-10 with 0 being no pain and 10 being worse pain ever felt. Baseline pain will be measured immediately after being stung for 2 minutes without any treatment. Subsequent pain felt at every 2 minutes for 30 minutes, at 1 hour post sting, and at 24 hours post sting will be based on changes from the original baseline pain. Mean change is defined as the mean change in pain from all time points measured from each participant and then averaged for each group. The control arm (placebo) was collected and analyzed in parallel to the treatment arm. The "mean change" for the treatment arm was then compared with the "mean change" for the control arm as a baseline. Hence, the data presented are the estimated effect for each treatment group compared to the control arms for each group.

Mean Change in Erythema (Redness) in the Treated Human Arm (Not Placebo) From Baseline Determined by Measures (3) Taken Over 24 Hours

Visual inspection of sting sites will be done at 30 minutes post sting (after treatment completed), 1 hour post sting, and 24 hours post sting. Erythema Index (EI) imeasures increase in cutaneous vasodilation. A computer-measured (Image-J software) EI was used to remove subjectivity. A numeric score was created for the level of erythema, with "0" representing baseline erythema on the control arm. Any positive number indicates more and negative number less erythema on treatment arm compared to placebo. EI values were measured on a "scale" from -20 to +20 with "0" being the midpoint where there would be equal amounts of erythema on both the treatment and control arm. The erythema they experienced on the "treatment arm" was then measured as more erythema (a positive value up to 20) or less erythema (a negative value up to -20).

Inclusion Criteria: Ages 18-65 years Healthy volunteers Exclusion Criteria: Known history of allergic reaction or anaphylaxis to prior Cnidaria sting of there envenomations Family history of anaphylaxis to any sting from either Cnidaria, bee, or wasp Pregnancy