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Swimmer’s itch


Swimmer’s itch is a non-contagious rash that appears on your skin after swimming or wading outdoors. It is also known as cercarial dermatitis. It occurs due to a certain parasite found in fresh or salt water. When you swim in water contaminated with that parasite, it burrows into your skin and causes an allergic reaction. This can lead to the formation of rash and itching. These parasites die after a few days, and the rash disappears after a few days without any complications. 


Swimmer’s itch results due to parasites that live in birds and other mammals living close to ponds and lakes. The parasites that commonly infect humans are Trichobilharzia and Gigantobilharzia. These parasites complete their lifecycle in birds that live close to water. Host birds include geese, ducks, and gulls.  The eggs of these parasites enter the water through animal feces. When they hatch, they live for some time in snails that are found near the shoreline. For this reason, swimmers’ itch is more common among people who swim in shallow water. This infection is not contagious and cannot transfer from one infected person to another through direct or indirect touch. 

Risk Factors And Epidemiology

Swimmer’s itch can occur in anyone who swims or wades in infested water. Children are particularly at higher risk of getting contaminated because they often play in shallow water and do not dry themselves off later. Adults can also get an allergic reaction if they spend too long in water that has been infested with parasites.

According to a study, the incidence of swimmers’ itch was 6.8 episodes per 100 water-exposure days. Cases of this infection are found throughout the world and are most common during the summer season because that’s when people go swimming or wading in the water. 

Signs And Symptoms

The most common symptom of a swimmer’s itch is a reddish-pink rash on your skin after swimming in fresh or salty water. The rash appears as small pimples, bumps, or blisters usually seen on exposed areas of your skin. The rash causes itchiness because the parasites burrow into your skin and trigger an allergic reaction. If you have already been exposed to swimmer’s itch parasites, the symptoms may worsen upon repeated exposure. 


Currently, no specific tests are available to diagnose swimmers’ itch. Blood tests may show an increased number of eosinophils. It is also difficult to differentiate swimmers’ itch from other types of skin diseases that present with a rash. Your doctor will need a complete history to suspect if you have a swimmer’s itch. If you have done swimming or wading recently in lake or pond water, mention it to your doctor. It is also important to remember that rash or itchiness after swimming in water can also develop due to other causes. 

Differential Diagnosis

The symptoms of swimmer’s itch can resemble rash or itchiness from other skin diseases. Common diseases include contact dermatitis, poison ivy rash, pseudomonas folliculitis, sea bather’s eruptions, seaweed dermatitis, Dogger Bank itch, urticaria, insect bites, acute schistosomiasis, and exposure to other ocean-dwelling organisms. Differentiation is done based on the history of exposure, the onset of symptoms, and duration. 


A swimmer’s itch usually does not require any treatment. The parasites cannot survive for long in the burrows of your skin and die within a week or two weeks. During this duration, you can use over-the-counter medications to reduce itching. Some home remedies can also be utilized to relieve symptoms. These include applying a cold compress, taking a bath with oatmeal or Epsom salts, or making a paste with baking soda plus water and applying it over affected areas. These techniques are supposed to reduce itching and relieve it, although they may not work for everyone. It is recommended not to scratch too hard on these rashes as they may worsen or cause other skin issues. Avoid going into fresh or salty water for a few weeks to prevent the risk of repeated exposure. Repeated exposure can exacerbate the symptoms of this infection.


Anti-allergic medications such as hydroxyzine or lotions containing calamine can be used to treat itchiness caused by this disease. If you have a severe itching issue, your doctor may prescribe topical corticosteroid creams to the affected areas. 


Swimmer’s itch occurs as an allergic reaction to parasites that are present in water. It fades away on its own when those parasites die, and your body heals itself. With or without treatment, it can take about two weeks to recover from this parasitic infection.


A few techniques can be used to prevent swimmers’ itch. After you’re done swimming, rinse off your body with clean water and dry your skin afterward with a clean towel. This can help in getting rid of possible parasites. Try to avoid places that have a known risk of swimmer’s itch. Some places have signs that warn about this condition. Shallow waters or marshy areas are more likely to be infested with parasites, so avoid going into such places. If you are a swimmer, prefer deeper water for swimming. Do not feed birds in areas where people are swimming because birds may carry parasites. Children should be specially guided to take a shower with clean water after swimming and dry themselves. Avoid staying in fresh or salty water for too long because the longer you stay, the higher the risk of infestation gets.

Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on May 09, 2023.





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