Itching after cooling in water: How to protect yourself against bath dermatitis
During the current heat wave, many Germans seek to cool off in local lakes or rivers. Unfortunately, after bathing in such waters, red, itchy wheals sometimes form on the skin. An expert explains how to protect yourself from so-called bath dermatitis.
Bathing dermatitis can be caught while bathing
In the current heat, there is nothing better than cooling off while bathing. However, going for a swim in a lake or river runs the risk of catching bathing dermatitis (cercaria dermatitis). This skin disease is also known by names such as duck fleas, bird billharziasis, dog leaves and water tumbling. An expert explains what is behind it and how you can protect yourself against it.
Never scratch, even if itchy
If the skin is covered with red, itchy spots after bathing, this can indicate bathing dermatitis (cercaria dermatitis).
“Cerciferous dermatitis can be very uncomfortable. But it is usually completely harmless and heals without consequences, ”explains Dr. Frank Meiß, acting senior consultant at the Department of Dermatology and Venereology at the University Medical Center Freiburg, in a message.
As it says, swollen wheals of up to eight millimeters in size on the skin are typical of pronounced cercaria dermatitis.
The redness can itch much more than a normal mosquito bite.
"It is important that the spots are not scratched open. Otherwise the wound may become inflamed, ”said Meiß.
Small hardenings form after a few days, which usually heal without consequences after three weeks at the latest.
Creams for mosquito bites and mild allergies can help to relieve the itching. If that is not enough, a doctor should be consulted. This can help with cortisone-containing creams and antihistamines, among other things.
Larvae confuse humans with ducks
As the University Medical Center Freiburg explains, the complaints are caused by larvae of suction worms, so-called cercariae, which occur in the water.
These get into the water from snails and then actually burrow into the skin of waterfowl, where they can continue to grow.
According to the experts, humans are a false host. The larvae mistake it for a water bird and then die of their own accord in human skin.
Violent reactions often only after the second bath
The complaints often only appear when swimming repeatedly in lakes and rivers. The reason for this is an allergic reaction in the body.
When the larvae penetrate the skin for the first time, the body develops a defense reaction that is weak and delayed.
It may tingle or itch slightly about ten minutes after swimming. The red spots are about two millimeters in size and disappear within a few days.
A pronounced cercaria dermatitis only occurs in the second infestation. Because then the immune defense reacts quickly and very effectively. In such cases, we speak of a sensitization phenomenon, a type of new allergy learned by the body.
Helpful tips for avoiding cercaria dermatitis
The University Medical Center Freiburg has summarized a few tips that help to avoid bath dermatitis:
- Rub with sunscreen or other fatty creams before bathing
- Avoid flat and plant-rich bank areas. Because here live the water snails that give off the cercariae
- Dry quickly and thoroughly after bathing
- Change swimwear after swimming
- Take special care with water temperatures above 20 degrees Celsius
The Ministry of Environment, Health and Consumer Protection of the State of Brandenburg has a further note in a leaflet: Pay attention to information or warning signs on site and, if necessary, do not bathe in affected waters. (ad)
Author and source information
This text corresponds to the specifications of the medical literature, medical guidelines and current studies and has been checked by medical doctors.