[1] Evidence Based Hlth Care Ltd, Edinburgh, Midlothian, Scotland
[2] Univ Edinburgh, Allergy & Resp Res Grp, Ctr Populat Hlth Sci, Edinburgh EH8 9AG, Midlothian, Scotland
[3] St Marys Hosp, David Hide Asthma & Allergy Res Ctr, Newport, Wight, England
[4] Univ Southampton, NIHR Southampton Resp Biomed Res Unit, Southampton, Hants, England
[5] Univ Hosp Southampton NHS Fdn Trust, Southampton, Hants, England
[6] Univ Southampton, Fac Med, Human Dev & Hlth Acad Unit, Southampton SO9 5NH, Hants, England
[7] Padua Gen Univ Hosp, Padua, Italy
[8] Charite, Dept Dermatol & Allergy, Allergy Ctr Charite, D-13353 Berlin, Germany
[9] Univ Hosp Osped Riuniti, Ancona, Italy
[10] Hosp Valle De Hebron, Barcelona, Spain
[11] Univ Groningen, Univ Med Ctr Groningen, Dept Paediat, Div Paediat Pulmonol & Paediat Allergy, Groningen, Netherlands
[12] Univ Groningen, Univ Med Ctr Groningen, GRIAC Res Inst, Groningen, Netherlands
[13] Natl Univ Ireland Univ Coll Cork, Dept Paediat & Child Hlth, Cork, Ireland
[14] Childrens Hosp, Geneva, Switzerland
[15] IdISSC, Hosp Clin San Carlos, Dept Allergy, Madrid, Spain
[16] Odense Univ Hosp, Hans Christian Andersen Childrens Hosp, DK-5000 Odense, Denmark
[17] Kings Coll London, Div Asthma Allergy & Lung Biol, Dept Pediat Allergy, London WC2R 2LS, England
[18] Kings Coll London, MRC, Kings Hlth Partners, London WC2R 2LS, England
[19] Kings Coll London, Asthma UK Ctr Allerg Mech Asthma, London WC2R 2LS, England
[20] Univ Hosp Charite, Allergy Ctr Charite, Berlin, Germany
[21] Univ Munich, Dept Dermatol & Allergy, Munich, Germany
[22] Coimbra Univ Hosp, Immunoallergol Dept, Coimbra, Portugal
[23] Univ Amsterdam, Acad Med Ctr, Emma Childrens Hosp, Dept Pediat Resp Med & Allergy, NL-1105 AZ Amsterdam, Netherlands
[24] Harvard Univ, Brigham & Womens Hosp, Sch Med, Div Gen Internal Med & Primary Care, Boston, MA 02115 USA