Bathing dermatitis: An itchy rash threatens when bathing in the lake
With the current summer temperatures there is nothing better than cooling off while bathing. If you go swimming in a lake, you should be careful because cercariae occur more often in some waters. These small larvae can trigger an itchy rash in humans.
Rash from tiny larvae
Anyone who is currently cooling off in bathing lakes runs the risk of catching bathing dermatitis (cercaria dermatitis). This itchy rash is triggered by cercariae. These are larvae of small suction worms (trematodes) that normally live in the internal organs of water fowl in Central Europe. With the bird droppings they get into the water, where they infect the snails (“intermediate host”) living in the bank area. To protect yourself, certain areas of water should be avoided.
Pathogens cannot be seen with the naked eye
If the skin itches after the bathing trip and red wheals form, many quickly think of possible insect bites.
But the cause of the rash can also be cercariae. The causative agents of bath dermatitis cannot be seen with the naked eye.
These are microscopic larvae that can occasionally occur in bathing water, especially with a high population of ducks and waterfowl, during the bathing season.
The Ministry of the Environment, Health and Consumer Protection of the State of Brandenburg reports in an information sheet, especially in high summer with long-lasting summer weather with water temperatures above 20 degrees.
Cercariae mostly stay on the water surface. Whether the larvae can be found more in a lake or not says nothing about the water quality. According to EU law, the authorities are not obliged to examine bathing water for cercariae.
Children and allergy sufferers are particularly at risk
If cercariae pierce human skin, they die shortly afterwards, but can trigger dermatitis.
"Cercaria or bath dermatitis is a long-known and usually uncomplicated skin disease that usually resolves without consequences," write the experts.
Initially there is a mosquito-like local reaction of the skin. Allergic reactions can occur, including the formation of red spots, which can reach a diameter of about half a centimeter after 24 hours.
On the following days, itchy wheals form, which only subside after ten to 18 days. "Children and allergy sufferers are particularly at risk," says the information sheet.
"If symptoms occur after bathing, such as skin irritation or wheals, a doctor should be consulted and the responsible health department informed," said the experts.
Symptoms such as nausea and vomiting, fever and sometimes even shock can occur in particularly sensitive people.
Then, according to the Brandenburg Ministry of Health, an emergency doctor must be called.
Incidentally, swallowing cercariae does not lead to disease. A transmission from person to person is also not possible.
Avoid bank areas
To protect yourself, you should avoid riparian zones and reed-rich areas where water snails predominate. In addition, attention should be paid to information or warning signs on site.
Applying water-repellent sunscreen or petroleum jelly makes it difficult for the cercariae to penetrate.
After bathing you should take a shower, dry your body thoroughly and change your swimwear.
If symptoms nevertheless occur, preparations that relieve inflammation and itchiness can help to treat the itchy rash.
"In order to generally reduce the concentration of cercariae in the water, no ducks should be fed in the vicinity of swimming areas," recommends the Schleswig-Holstein Nature Conservation Association (NABU) on its website.
"The more food, the more ducks, more feces and more cercariae." (Ad)