Rash on legs on every visit to Italy

Way back in 2009 I woke up one morning in Italy to find small itchy spots (like pinpricks) on the front of both legs above the ankle. Not insect bites. They cleared up back at home but sometimes flared up briefly in the bath and felt itchy. I've had had a week in Italy in the last 3 years, in early May when it's not hot, and each time a rash appears on my legs (between ankle and knee), most unsightly but otherwise it does not bother me. Within a few days of coming home it clears up. I use only my own toiletries, not the hotel ones. I'm having a week in Italy shortly - any suggestions about the cause or how to avoid it would be very appreciated.