Seabather’s Eruption or Sea Lice - Causes, Symptoms, Diagnosis, and Treatment

What Is Seabather’s Eruption?

The seabather's eruption or sea lice, was first described in 1949 on the eastern coast of Florida. It was called 'Pica-Pica', which means 'itchy-itchy' in Spanish. It is characterized by itchy and papular lesions on the skin after prolonged exposure to seawater. The main causative agents responsible for this condition are the thimble jellyfish and a sea anemone. These organisms can get easily entrapped between the skin and the swimsuit. When trapped between the skin and swimsuit, they release various antigenic toxins responsible for the pruritic (itchy) and papular rashes in the host.

The larvae of thimble jellyfish were considered the main culprit earlier; however, recent studies show that the other jellyfish stages are also responsible for this condition. Children below 15 years old are more vulnerable to this condition as they tend to spend more time in seawater than adults. Surfers and individuals who have a prior history of the condition are also at higher risk.

Even though it is also known as sea lice, the term is not so accurate for the condition as sea lice are fish parasites and are unrelated to seabather's eruption. It is also different from a swimmer's itch, as a swimmer's itch affects the uncovered areas of the body. In contrast, a seabather's eruption is seen on body areas covered with a bathing suit. Seabather's eruption does not cause many serious symptoms and can be easily treated at home.

What Causes Seabather’s Eruption?

The main causative agents for the seabather's eruption are all the free-swimming stages (larvae stages) of thimble jellyfish and the larval stage of the sea anemone, Edwardsiella lineata.

These organisms get entrapped in the bathing suits or hair of individuals while bathing in seawater. They have specialized stinging cells that get activated by mechanical pressure changes, osmotic changes due to evaporation or when rinsing off with fresh water. When the swimmer gets out of the seawater, and the water drains out, these organisms may remain between the swimsuit and the skin. These can cause pressure on the jellyfish, leading to the activation of stinging cells. Once the stinging cells are activated, they release toxins into the skin. The initial rash can be due to toxins, and further development of a rash can vary in individuals as it is immune-mediated. Not every individual exposed to the toxins develops severe rashes.

At What Location and Time Does Seabather’s Eruption Typically Occur?

The larvae responsible for seabather’s eruption only inhabit saltwater oceans and seas, not freshwater lakes. Sea lice are most prevalent along the coasts of Florida and the Caribbean. The likelihood of encountering this issue is higher from March through August, with peaks in May and June. Sea lice larvae can be unpredictable, as they come and go with ocean drifts and the Gulf Stream.

What Are the Symptoms Associated With Seabather’s Eruption?

A seabather’s eruption can often be identified by examining the rash pattern. A sea lice rash affects areas covered by a bathing suit, so it is not usually visible on the legs, arms, hands, and feet. However, it may also be found on the head, facial hair, or areas with dense body hair where sea lice become trapped or pressed against the skin. If swimming with sea lice, one is likely to develop a reaction within 24 hours. Sometimes, the reaction can occur minutes after leaving the water or even hours later.

The symptoms associated with seabather's eruption include;

• Skin discomfort (tingling sensation) while in water or as soon as one is out of water.

• The appearance of extremely itchy rashes, hard or soft bumps, or even blisters. Rashes can be itchy for several hours to weeks and can last up to one to two months.

• Rashes can be painful in severe cases.

• The appearance of rashes is confined to the area under the bathing suit, which aggravates while taking a bath in freshwater.

Rare signs and symptoms associated with the condition include;

• Nausea.

• Sore throat.

• Fever.

• Cough.

• Diarrhea.

• Abdominal pain.

• Fatigue.

How to Diagnose a Seabather's Eruption?

The diagnosis of seabather's eruption includes the history of exposure and the physical examination. Laboratory studies, biopsy, or radiographic studies are not so helpful in diagnosing seabather's eruption.

What Is the Differential Diagnosis of Seabather’s Eruption?

The differential diagnosis of Seabather's eruption includes;

• Arthropod bites (insects, scorpions, crabs, and more)

• Folliculitis.

• Allergic contact dermatitis.

• Acute urticaria.

• Swimmer's itch.

• Seaweed dermatitis.

What Is the Treatment for Seabather’s Eruption?

The treatment for Seabather's eruption includes symptomatic or supportive therapy. The supportive therapy includes the use of 5 percent acetic acid (diluted vinegar), topical corticosteroids, and systemic antihistamines. When one notices the eruption after removing the costume and taking a shower, the application of diluted vinegar can prevent stinging cells from secreting toxins further. Apply an ice pack to relieve the pain.

Topical corticosteroids like 1 percent Hydrocortisone and antihistamines can be very effective in treating rashes. Systemic corticosteroids are given when symptoms like headaches, fatigue, chills, and vomiting, are present. Nonsteroidal anti-inflammatory drugs can be given if pain and inflammation are present. However, it is not recommended for children.

Allergies or diseases affecting the immune system can increase the severity of the condition. If the symptoms are getting severe, the patient may require hospitalization, even though it is a rare case. There are chances that stinging cells may remain in the swimming garment even after a shower. So, the cloth should undergo machine washing or be washed using hot water and detergent before being used the next time.

What Are the Complications of the Seabather's Eruption?

The rashes from the seabather's eruption may take one to two months to settle. If there is further exposure to the causative organism, the reaction can be more severe due to allergic hypersensitivity to the disease. There have been cases where the symptoms were very severe due to continuous episodes of the seabather's eruption. Such individuals should avoid seawater during the seasonal peaks. Wearing swimsuits for an extended period after swimming, taking a bath in freshwater, and mechanical stimulation (wiping with a towel) can complicate the condition.

How to Prevent Seabather’s Eruption?

There is no effective measure to prevent a seabather's eruption other than staying out of seawater.

Here are a few ways to avoid a potential encounter with sea lice or at least minimize the risk of developing a severe rash:

• Check for beach updates from the local health department. If sea lice have been reported, notices will likely be posted. It is advisable to avoid swimming in that area until it is deemed safe to do so.

• It is safe to avoid swimming during the seasonal peak of jellyfish.

• Avoid t-shirts and one-piece bathing suits, as they tend to trap more larvae.

• One must avoid wearing a swimsuit for a prolonged period of time and try to take a shower with a bathing suit off whenever possible.

• One must not rub the affected areas, as it can worsen the condition.

• Do not wear the same clothing again without deep washing.

Things to Take Care of Before Showering After Swimming

Immediately after swimming, remove all swimwear, including swimsuits and rash guards, and rinse off with unaffected salt water. Freshwater can sometimes irritate sea lice larvae and exacerbate stinging by disrupting their chemical balance. After rinsing with salt water, showering is safe. The duration of the shower and water temperature are not significant, but removing swimwear first is essential.

Conclusion:

Seabather's eruption is a condition that can affect any individual. There should be more awareness about this condition. People who are so fond of seawater can take appropriate preventive measures and the situation can be less panicky. There are no cases exhibiting symptoms of anaphylaxis or deaths relating to this condition. Seabather's eruption has an excellent prognosis with simple home remedies in most cases.