For the last 8 years i have experienced painfully itchy legs after contact with cold water, sea water, pool water or even rain. the only treatment seems to be to run by legs under scolding hot water.

Aquagenic itch: This is a skin disorder in which contact with water makes the skin itch for an hour or so. The cause is unknown but it may be hereditary. Cool water can release histamine and other substances that cause severe itching. Antihistamines are prescribed for relief. A dermatologist, especially in an academic institution, should have more information about this topic and can advise you best.