ALERT

For the latest coronavirus care instructions and resources, please call our COVID-19 hotline at 208-381-9500. Find additional information and resources here and learn more about how we’re working to keep you healthy and safe.

toggle mobile menu Menu
toggle search menu

Site Navigation

Supplemental

Menu

Jellyfish Stings: Allergic Reaction

Jellyfish Stings: Allergic Reaction

Topic Overview

The reaction that you have to a jellyfish or Portuguese man-of-war sting depends on many things. The potency of the venom changes with the type of jellyfish and also is stronger during some seasons than in others. Other things that affect the severity of your reaction include:

  • Your size, age, and general health.
  • The location and how much of your body (surface area) was stung.
  • The size or number of jellyfish or tentacles that stung you.

The pain from jellyfish and Portuguese man-of-war stings may be intense and may last for several hours. The skin at the site of the stings may look dusky or bluish purple. Blisters and deep sores (ulcers) may develop. Healing is generally a slow process that may take many weeks. Permanent scars may occur at the site of a sting.

Small children are at risk for stings in the mouth if they put a jellyfish or portion of a tentacle in their mouths. A sting to the mouth or throat can cause sudden and severe swelling, which can be life-threatening.

Problems from jellyfish or Portuguese man-of-war stings may develop right away or be delayed for several hours or days. A severe allergic reaction (anaphylaxis) may affect any body system and require emergency care. Symptoms can include any of the following:

  • Shock
  • Severe pain
  • Swelling of the lips, tongue, mouth, throat, neck, ears, eyelids, palms, or soles of the feet (angioedema). Swelling is most serious when it involves the airway and interferes with breathing.
  • Coughing, wheezing, difficulty breathing, or a feeling of fullness in the mouth, throat, or neck
  • Lightheadedness, confusion, or agitation
  • Headache, dizziness, or vertigo
  • Nausea, vomiting, diarrhea, and stomach cramps
  • Fever and chills
  • Hives and flushing of the skin. These symptoms often occur with other symptoms of a severe reaction.
  • Muscle spasm, muscle cramps, joint pain, or generalized aching

Related Information

Credits

Current as of: June 26, 2019

Author: Healthwise Staff
Medical Review: William H. Blahd Jr. MD, FACEP - Emergency Medicine
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine
David Messenger MD

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. Healthwise is a URAC accredited health web site content provider. Privacy Policy. How this information was developed to help you make better health decisions.

© 1995-2015 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.