I found this article and thought others might be interested. http://www.jfponline.com/pdf%2F5606%2F5606JFP_ClinicalInquiries5.pdf
Interesting, Aznalla... I can't take sulfonamide antibiotics....I get the terrible itching, and occasionally hives. However, I have no side effects from taking Maxzide (triamterene/hydrochlorothiazide) - a non-antibiotic sulfonamide.
If I read it correctly it says there is increased risk of allergy to the sulfa based diuretic if you had allergy to sulfa antibiotics. But not a one to one correlation. I have had hives from sulfa antibiotic but not to maxide. I don't tolerate it for reasons unrelated (I think) to the sulfa issue. Still it is something to keep in mind if I ever start taking a diuretic again.