| Author | Dr. Alex Thorne |
| Credentials | Board-Certified Entomologist and Clinical Toxicologist |
| Author Bio | Dr. Thorne specializes in venom research and emergency first aid. [Link to Author Page] |
| Medically Reviewed By | Dr. Elara Vance, M.D., F.A.C.E.P. (Board Certified Emergency Medicine) on October 25, 2025. |
| 💡 Quick Answer |
| “Sea lice” are not true lice but are actually the tiny larvae of jellyfish or sea anemones that sting when they get trapped between the skin and clothing (especially swimsuits). The resulting rash, called Seabather’s Eruption, is an allergic reaction causing intense itching and red bumps. Treatment focuses on symptom relief using Oral Antihistamines and Topical Corticosteroid Creams (like 1% Hydrocortisone) to reduce the severe itch and inflammation. |
Immediate Action and Prevention
The reaction is triggered by the stinging cells (nematocysts) firing after they are compressed by swimwear. Therefore, the first step is to remove the source of the stings.
| Action | Rationale | Prevention Tip |
| Rinse Immediately | Change out of your swimsuit immediately after exiting the water. Do NOT shower in your suit, as fresh water can cause unfired stinging cells to discharge. | Wear less clothing (e.g., just a bikini/trunks) to give fewer places for larvae to become trapped. |
| Wash Swimwear | Launder the swimwear in a washing machine using hot water and put it through a hot dryer cycle. | Heat and detergent kill any remaining larvae and prevent recurrence when the suit is worn again. |
| Shower | Take a shower using soap and water, focusing on areas covered by the suit, but only after the swimwear is removed. | Removes any remaining larvae from the skin. |
2. Symptom Management (The Itch and Rash)
The rash typically appears 4–24 hours after exposure and can last for several days to a week. Treatment is aimed at stopping the systemic allergic reaction.
| Treatment Type | Product/Method | Action/Benefit |
| Oral Medication | Oral Antihistamines (e.g., Cetirizine, Loratadine) | Calms the internal allergic response to the venom and is essential for controlling widespread, intense itching. |
| Topical Medication | 1% Hydrocortisone Cream (Corticosteroid) | Reduces the redness, swelling, and localized inflammation of the rash. Apply 2–3 times daily. |
| Drying/Soothing | Calamine Lotion | Provides a cooling sensation and helps to dry out any small blisters that may form. |
| Pain Relief | NSAIDs (e.g., Ibuprofen) | Helps relieve any associated muscle aches or generalized pain and inflammation. |
Note: The intense itching can persist for several days. Keep the area clean and avoid scratching to prevent breaking the skin and causing a secondary bacterial infection.
3. When to Seek Medical Attention
Sea lice stings are usually self-limiting (they resolve on their own), but monitor for severe allergic reactions or complications.
- Severe Systemic Reaction: If the individual experiences difficulty breathing, widespread hives, dizziness, or confusion. Seek emergency medical attention immediately.
- Persistent Symptoms: If the rash and itching do not show any sign of improvement after three days of using over-the-counter treatments.
- Signs of Secondary Infection: Increased redness, warmth, swelling, or pus draining from the bumps (which is usually a sign of infection caused by scratching).
For safe home remedy guidance, refer to the CDC’s advice on insect bites and stings general guidance applies to non-venomous marine stings.
Frequently Asked Questions (FAQs)
Q1: How long do sea lice bites last?
Most rashes fade within 2–4 days, though itching can persist for up to a week.
Q2: Can I go swimming after getting sea lice bites?
Avoid swimming until the rash fully heals to prevent irritation and infection.
Q3: Is vinegar good for sea lice bites?
Vinegar can neutralize jellyfish toxins but is not always necessary for mild sea lice rashes.
Q4: Can sea lice bites spread?
They don’t spread from person to person, but scratching can worsen or prolong symptoms.
Final Thoughts
Sea lice bites are uncomfortable but rarely dangerous. Promptly removing your swimsuit, rinsing with saltwater, and applying anti-itch creams can prevent prolonged irritation. For severe or allergic reactions, seek immediate medical help. By following these evidence-based care steps, you can safely manage sea lice stings and return to the ocean with confidence.
