[1] Univ Helsinki, Hosp Skin & Allerg Dis, Dept Dermatol, Helsinki 00250, Finland
[2] Univ Amsterdam, Dept Dermatol, Amsterdam, Netherlands
[3] Div Dermatol, Vancouver, BC, Canada
[4] Great Ormond St Hosp Sick Children, Dept Paediat Dermatol, London WC1N 3JH, England
[5] Univ Dusseldorf, Hautklin, D-4000 Dusseldorf, Germany
[6] Turku Univ Hosp, Dept Dermatol, FIN-20520 Turku, Finland
[7] Hop Nord St Etienne, Serv Dermatol, St Etienne, France
[8] Royal Free Hosp, London NW3 2QG, England
[9] Hop Pellegrin Enfants, Unite Dermatol Pediat, Bordeaux, France
[10] Univ Toronto, Div Dermatol, Toronto, ON, Canada
[11] Univ Liverpool, Dept Dermatol, Liverpool L69 3BX, Merseyside, England
[12] Univ Hosp Lewisham, Dept Dermatol, Skin Therapy Res Unit, London, England
[13] Univ Klinikum Tuebingen, Hautklin, Tubingen, Germany
[14] Hop Necker Enfants Malad, Serv Dermatol, F-75730 Paris, France