Help map human cercarial dermatitis (swimmer’s itch) in the UK

What is human cercarial dermatitis?

Human cercarial dermatitis (HCD or swimmer’s itch) is a temporary, allergic contact dermatitis caused by the larvae of some species of marine or freshwater bird and mammal parasites. These free-swimming larvae (cercariae) emerge from aquatic snails, accidentally penetrate the skin of humans in the water and are then usually killed by the allergic response. The symptoms can include an initial prickling sensation, intense itching, small reddish bumps and sometimes blisters.  Symptoms can develop in minutes to days after exposure and last for up to two weeks. The more a person is exposed, the faster the reaction occurs with more intense symptoms. This condition is not contagious.  The incidence of HCD is increasing, possibly due to higher water temperatures, but also increased recreational use of water habitats, better monitoring and reporting. 

How you can help

We do not have accurate records on the distribution of HCD in the UK, so the Molecular Parasitology Group at Kingston University London is mapping reported sites as part of a project to increase our understanding of HCD and how it affects recreational users of water.

If you have experienced HCD, please take part in the survey at: https://app.onlinesurveys.jisc.ac.uk/s/kingston/human-cercarial-dermatitis-distribution

You will be asked for the name of the water body where you experienced HCD, which county it was in, the year and (if possible) the month and how long the symptoms lasted.  All responses are anonymous.

Thank you.

Dr Ruth Kirk
Visiting Senior Fellow in Parasitology
Molecular Parasitology Laboratory
School of Life Sciences, Pharmacy & Chemistry
Faculty of Health, Science, Social Care & Education
Kingston University