Sea Lice 101: Guide for Pharmacists


Summer can be a fun time to explore or vacation at beaches, but what you may not realize is sea lice could be lurking in the ocean.

Summer can be a fun time to explore or vacation at beaches, but what you may not realize is sea lice could be lurking in the ocean. Unfortunately, sea lice have begun infesting northwest Florida around Pensacola Beach. Sea lice have actually been documented along Florida’s coast since the 1900s.1 Pharmacists can play an important role in sea lice management and sharing prevention tips to help patients have a fun and safe summer.

Sea Lice Facts

Sea lice is scientifically referred to as Sea Bather’s Eruption, and the peak months of occurrence are generally March through August.2 There has been an increase in cases reported in the recent years most likely due to shifts in the ocean currents. Sea lice are actually the larvae of jellyfish, commonly a small species known as thimble jellyfish. These miniature jellyfish can become trapped under bathing suits or surf boards in the ocean, and stinging cells are activated causing pruritus, and sometimes systemic symptoms including fever, weakness, nausea, vomiting, and diarrhea.2 Additionally, sea lice can affect both adults and children. Individuals can experience a 'prickling' sensation while in the water. However, pruritus generally begins several hours after being in the ocean and lasts about 2 to 4 days, but can persist for up to two weeks.1 It is important to note that sea lice has no relation to head lice.


Patients can usually self-treat sea lice with supportive care using over-the-counter products. Advise patients that an oral antihistamine, such as Benadryl (diphenhydramine), along with topical hydrocortisone cream can be used to relieve the itching.1,2 Bathing in a colloidal oatmeal preparation, and applying calamine lotion can also provide comfort to patients.2 It is important to avoid using multiple antihistamines at the same time to avoid toxic effects, especially in children. Remind patients that diphenhydramine can cause drowsiness. Systemic corticosteroids should generally be avoided unless patients develop severe symptoms. Acetaminophen can be used to manage fever in children. Additionally, children’s finger nails should be shortened to avoid scratching the lesions.

Prevention Strategies

Advise patients to be on the lookout for local beach reports, and check with their hotel for important information. Blue and purple flags indicate that dangerous marine life can be present in the ocean, and therefore individuals should exercise caution, and probably avoid the water under these circumstances. Instead, using the pool facilities would be a safer option to prevent sea lice. The sea lice currently affecting Florida beaches are almost impossible to spot in the ocean as they are no larger than a speck of ground pepper.

After swimming in the ocean, individuals should change out of their bathing suits as soon as possible and shower.1,2 Showering can help to prevent seabather’s eruption by removing loose larvae. Children should avoid sitting in wet bathing suits while in a car seat, as this can increase the risk of developing a rash. Bathing suits should also be thoroughly washed with detergent and heat-dried after use, which can also prevent sea lice recurrence.2


  • Florida Health Palm Beach County. Sea lice. Florida Heath website. Accessed July 10, 2018.
  • Russell MT, Tomchik RS. Clinical articles seabather’s eruption or “seal lice”: new findings and clinical implications. Florida Department of Health website. Accessed July 10, 2018.

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