piojos de mar

Piojos de Mar: Understanding the Irritation and Effective Treatment


Sea lice bites, commonly known as “piojos de mar” in Spanish, refer to skin irritation caused by the entrapment of small jellyfish larvae under bathing suits while swimming in the ocean. This article explores the symptoms, causes, treatment options, contagiousness, prevention measures, and important takeaways regarding sea lice bites.


Sea lice bites manifest through various symptoms, which may include:

Immediate Symptoms

  • Prickling sensations upon contact with the larvae.
  • Itching of the affected area.

Additional Symptoms

  • Headaches
  • Lethargy
  • Nausea
  • Development of a rash under the bathing suit area
  • Formation of red bumps that can merge, creating a large, red mass.

It is worth noting that although sea lice larvae may cling to hair, they should not be confused with head lice.


Sea lice bites, or sea bather’s eruption, predominantly occur during warm summer months when thimble jellyfish and anemone larvae are brought closer to the shoreline by winds. Specifically, areas such as Palm Beach and Broward counties in Florida, where Gulf Stream winds blow currents, report higher incidents of sea lice bites. The larvae, equipped with stinging cells called nematocysts, become trapped inside bathing suits during oceanic activities. The resulting friction between the larvae and the skin leads to the characteristic skin irritation known as sea lice bites. Wearing tight bathing suits or rubbing a towel against the skin exacerbates the condition. Additionally, failure to wash or dry swimsuits properly can contribute to sea lice bites, as the non-living stinging cells can remain on the clothing.


Over-the-counter treatments are generally effective in treating sea lice bites. One recommended approach involves applying 1 percent hydrocortisone cream to the affected areas two to three times a day for one to two weeks, thereby reducing itching and inflammation. Other strategies to alleviate symptoms include:

  • Applying diluted vinegar or rubbing alcohol to soothe irritated areas.
  • Using cloth-covered ice packs to relieve discomfort.
  • Taking nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen or aspirin (note: aspirin should not be given to children under 18 years old), to alleviate pain and inflammation.

In severe cases, where individuals experience an intense reaction to sea lice bites, seeking medical attention is advisable. Oral corticosteroids, such as prednisone, may be prescribed by a doctor.

With appropriate treatment, sea lice bite symptoms typically subside within four days.


Sea lice bites themselves are not contagious. Once an individual develops the sea lice bites rash, it cannot be transmitted to others. However, if a swimsuit is loaned to someone without being washed, they may experience a rash due to the lingering stinging cells. Therefore, it is essential to wash swimsuits thoroughly and dry them using warm heat after each use.


While it is challenging to entirely prevent sea lice bites when stinging jellyfish larvae are present in the ocean, certain precautions can minimize the risk. Consider the following preventive measures:

  • Stay out of the water if there is an infestation of jellyfish larvae.
  • Apply barrier creams to the skin or wear wet suits as potential protective measures (although effectiveness may vary).
  • Pay attention to lifeguard stations and warnings regarding sea lice infestations.
  • Change into dry clothes promptly after swimming.
  • Rinse your skin with seawater that is known to be free of jellyfish larvae (avoid washing the skin with freshwater or vinegar immediately after leaving the water, as it can worsen the bites).
  • Gently pat the skin dry instead of rubbing it.
  • Wash all bathing suits thoroughly after each use.


Sea lice bites, also known as “piojos de mar,” are a common skin irritation caused by small jellyfish larvae. Although the symptoms can range from mild to severe, effective treatments are available over the counter. It is important to promptly address sea lice bites to alleviate discomfort and prevent complications. By following preventive measures and staying informed about sea lice infestations, individuals can enjoy oceanic activities with reduced risk of encountering these irritating bites.