Riva Beach Faces Swimmer’s Dermatitis Cases Due to Water Temperature and Bird Presence

A practically confirmed case at the Riva Emergency Room (where a Milanese girl covered in papules all over her skin and suffering from intense itching was treated on Wednesday afternoon: after a swim at Sabbioni beach) and at least a dozen “suspicious cases” reported in Riva pharmacies — all following a swim — and managed with antihistamines and some cortisone.

As every year (despite very few incidents in 2000), the so-called “itchy rash,” or swimmer’s dermatitis, seems to reappear. This highly annoying condition (talking about danger might be exaggerated) occurs on Riva’s beaches when two factors coincide: the presence of numerous wild birds (a constant) and water temperatures above twenty degrees Celsius (which, of course, is typical only in July).

Causes and Symptoms of Dermatitis

Dermatitis, which typically resolves within a few days without lasting effects, but which is genuinely bothersome (especially for unaware tourists), is caused by a parasite — the cercaria — that resides in lake snails (the limnaeas) and emerges in millions into the water during peak seasonal temperatures.

Humans are not the ideal hosts for the parasite (wild waterfowl are), but when the concentration is high, the cercaria can instead latch onto swimmers’ skin before dying inside it.

Papules, redness, and intense itching are the direct consequences of cercaria penetration on human skin.

How to Protect Against and Prevent Dermatitis

As suggested years ago by the well-known dermatologist Giuseppe Zumiani, immediately after exiting the lake water, a thorough shower and careful drying are recommended — this should be done individually.

Regarding broader prevention, it might be necessary to reduce the population of ducks, which, together with mollusks (difficult to eradicate), form the backbone of the parasite’s lifecycle.