Swimmer's itch or cercarial dermatitis, is a short-term allergic immune reaction occurring in the skin of humans that have been infected by water-borne schistosomes. Accessed Oct. 11, 2016. This site complies with the HONcode standard for trustworthy health information: verify here. Children may have the highest risk, since they tend to play in shallow water and are less likely to dry off with a towel. The itchy rash associated with swimmer's itch looks like reddish pimples or blisters. Inside the circulatory system, the immature worms (, Local water chemistry reduces the molluscicide's efficacy, Adjacent snail populations repopulate a treated area, This page was last edited on 9 August 2020, at 23:41. Nevertheless, the condition has been regarded as emerging infectious disease. Humans aren't suitable hosts, so the parasites soon die while still in your skin. Any use of this site constitutes your agreement to the Terms and Conditions and Privacy Policy linked below. What are the signs and symptoms of swimmer’s itch? Schistosomes spend their life cycle as parasites in the bodies of water snails and in the blood stream of aquatic mammals, ducks or other waterfowl. Some laboratory evidence indicates snails shed cercariae most intensely in the morning and on sunny days, and exposure to water in these conditions may therefore increase risk. Mayo Clinic is a not-for-profit organization. Auerbach PS, et al. Philadelphia, Pa.: Mosby Elsevier; 2012. http://www.clincalkey.com. Examples include: The parasite's eggs enter the water via their hosts' feces. See our safe care and visitor guidelines, plus trusted coronavirus information. Suttle Lake SISTERS, Ore. (KTVZ) -- Swimmer's itch, a skin rash that is caused by a very small parasitic worm, has been reported at Suttle Lake, northwest of Sisters. Swimmer's itch is an allergic reaction to microscopic parasites that burrow into your skin while you're swimming or wading outdoors. "Mayo," "Mayo Clinic," "MayoClinic.org," "Mayo Clinic Healthy Living," and the triple-shield Mayo Clinic logo are trademarks of Mayo Foundation for Medical Education and Research. [14] Work on schistosomiasis showed that water-resistant topical applications of the common insect repellent DEET prevented schistosomes from penetrating the skin of mice. But you can't get swimmer's itch from swimming pools that are treated with chlorine. Immature larval forms (cercariae), of parasitic flatworms (schistosomes), are released from infected snails into fresh and salt water, such as lakes, ponds, and lagoons. In addition, bathing in oatmeal, baking soda, or Epsom salts can also provide relief of symptoms. Other taxa reported to cause the reaction include Bilharziella polonica and Schistosoma bovis. A single copy of these materials may be reprinted for noncommercial personal use only. Cercarial dermatitis is common in freshwater, brackish and marine habitats worldwide. The results with this agent have been inconclusive, possibly because: More importantly, perhaps, copper sulfate is toxic to more than just molluscs, and the effects of its use on aquatic ecosystems are not well understood. [1] Cercarial dermatitis is common in freshwater, brackish and marine habitats worldwide. However, people repeatedly exposed to cercariae develop heavier symptoms with faster onset. Before infecting birds, other animals or people, the hatched parasites must live for a time within a type of snail. Incidencemay be on the ri… Advertising revenue supports our not-for-profit mission. Try to avoid scratching the rash. Symptoms of swimmer’s itch may include: tingling, burning, or itching of the skin; small reddish pimples; small blisters; Within minutes to days after swimming in contaminated water, you may experience tingling, burning, or itching of the skin. [11] Children may become infected more frequently and more intensely than adults but this probably reflects their tendency to swim for longer periods inshore, where cercariae also concentrate. [4] Orally administered hydroxyzine, an antihistamine, is sometimes prescribed to treat swimmer's itch and similar dermal allergic reactions. [11] Studies of infested lakes and outbreaks in Europe and North America have found cases where infection risk appears to be evenly distributed around the margins of water bodies[9] as well as instances where risk increases in endemic swimmer's itch "hotspots". Signs and symptoms of swimmer's itch typically worsen with each exposure to the parasites. These parasites can be released into the water. Check out these best-sellers and special offers on books and newsletters from Mayo Clinic. Symptoms, which include itchy, raised papules, commonly occur within 1–2 days of infection and do not generally last more than 2–3 weeks. 6th ed. Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic School of Continuous Professional Development, Mayo Clinic School of Graduate Medical Education, FREE book offer – Mayo Clinic Health Letter. Also known as cercarial dermatitis, swimmer's itch is most common in freshwater lakes and ponds, but it occasionally occurs in salt water. It may appear within minutes or days after swimming or wading in infested water. © 1998-2020 Mayo Foundation for Medical Education and Research (MFMER). Accessed Oct. 11, 2016. Swimmer's itch is a rash usually caused by an allergic reaction to parasites that burrow into your skin while you're swimming or wading in warm water. retrieved May 12, 2014, "Cercarial Dermatitis Transmitted by Exotic Marine Snail", "Public health importance and risk factors for cercarial dermatitis associated with swimming in Lake Leman at Geneva, Switzerland", "Efficacy of praziquantel in treating natural schistosome infections in common mergansers", 10.1645/0022-3395(2001)087[0424:EOPITN]2.0.CO;2, "Development and evaluation of LIPODEET, a new long-acting formulation of N, N-diethyl-m-toluamide (DEET) for the prevention of schistosomiasis", "CDC - Cercarial Dermatitis - Publications", https://en.wikipedia.org/w/index.php?title=Swimmer%27s_itch&oldid=972061400, Parasitic infestations, stings, and bites of the skin, Creative Commons Attribution-ShareAlike License, After infecting a snail, it develops into a mother, Cercariae use a tail-like appendage (often forked in, After locating a bird, the parasite penetrates through the skin (usually the feet), dropping the forked tail in the process. [17], CS1 maint: multiple names: authors list (, "Avian schistosomes and outbreaks of cercarial dermatitis", "With warm weather, Swimmers Itch makes annual appearance", In CDC. Swimmer's itch usually affects only exposed skin — skin not covered by swimsuits, wet suits or waders. The free-swimming … In Michigan, for decades, authorities used copper sulfate as a molluscicide to reduce snail host populations and thereby the incidence of swimmer's itch. However, people repeatedly exposed to cercariae develop heavier symptoms with faster onset. Swimmer's itch rarely leads to complications, but your skin can become infected if you scratch too vigorously. Aquatic skin disorders. Talk to your doctor if you have a rash after swimming that lasts more than three days. Swimmer's itch is a temporary, itchy rash caused by small worm-like parasites called schistosomes (shiss-toe-soams). These parasites use both freshwater snails and vertebrates as hosts in their parasitic life cycles as follows: Humans usually become infected after swimming in lakes or other bodies of slow-moving fresh water. [15] Public education of risk factors[16], a good alternative to the aforementioned interventionist strategies, can also reduce human exposure to cercariae. The parasites that cause swimmer's itch live in the blood of waterfowl and in mammals that live near ponds and lakes. [3], There are no permanent effects to people from this condition. Swimmer's itch is an itchy rash that can occur after you go swimming or wading outdoors. Also known as cercarial dermatitis, swimmer's itch is most common in freshwater lakes and ponds, but it occasionally occurs in salt water.Swimmer's itch is a rash usually caused by an allergic reaction to parasites that burrow into your skin while you're swimming or wading in warm water.The parasites that cause swimmer's itch normally li… Centers for Disease Control and Prevention. You might be referred to a doctor who specializes in skin conditions (dermatologist). It can also be caused by schistosome parasites of non-avian vertebrates, such as Schistosomatium douthitti, which infects snails and rodents. The parasites can get under your skin when you swim in freshwater (such as lakes and ponds) and sometimes salt water. Some work in Michigan suggests that administering praziquantel to hatchling waterfowl can reduce local swimmer's itch rates in humans. The condition was known to exist as early as the 1800s, but it was not until 1928 that a biologist found that the dermatitis was caused by the larval stage of a group of flatworm parasites in the family Schistosomatidae.