Swimmer's Itch





What is Swimmer’s Itch?

Swimmer’s itch or Duck itch is a skin rash (Cercarial dermatitis) caused by an allergic reaction to contact with certain parasites of birds and mammals. Snails become infected with these parasites and then release them in fresh and salt water. Swimmers itch generally occurs during the summer months.

What are the Symptoms of Swimmer’s Itch?

Symptoms include tingling, burning or itching of the skin within minutes or days after exposure. Small reddish bumps appear within 12 hours, which may develop into blisters. Itching may last up to a week or more, but will gradually go away.

Is Swimmers Itch a Health Hazard?

No. The swimmers itch parasite is not parasitic to humans and does not cause human diseases. No treatment is required for the rash. The rash will go away naturally within a few days, and there are no lasting effects. The same lotions used for mosquito bites and other itching rashes can control the itching caused by the rash. Swimmers itch cannot be spread from person-toperson.

Is Swimmer’s Itch Related to Water Quality?

No. The presence of swimmer’s itch is not related to pollution or poor water quality. It is a natural life cycle. Although it has been present in the state for many years, it hasn’t become a significant nuisance problem in most of New Hampshire lakes.

Is There Any Way to Prevent Swimmer’s Itch?

No. The adult parasite lives in the bloodstream of infected host animals such as ducks, geese, gulls, swans, as well as in certain aquatic mammals such as muskrat and beaver. The parasites produce eggs that are passed in the feces of the host bird or mammal. So when the animal feces land in the water, the water becomes contaminated.

How Do I Avoid Swimmer’s Itch?

  • Avoid swimming in areas where ducks and geese congregate, typically in sheltered coves and calm water.
  • Do not attract birds by feeding them in areas where people are swimming.
  • Avoid swimming near or wading in marshy areas where snails are commonly found.
  • Towel dry or shower immediately after leaving the water.
  • Avoid swimming in areas where swimmer’s itch is a known problem or where signs have been posted warning of unsafe water.


Life Cycle of 'Swimmer's Itch':










Contact the NHDES Beach Program to report Swimmer’s Itch in New Hampshire:

(603) 271-0698    or    beaches@des.nh.gov

Contact the SLA for more info on where you suspect Swimmer's Itch may occur, or if you would like to know more:

General info: (603) 968-7336    or    info@squamlakes.org
Tyson Morrill, SLA's Director of Conservation at tmorrill@squamlakes.org