Skin prick tests
All children underwent skin prick testing to common aeroallergens for our region (ALK-abelló, Hamburg) including house-dust mites (Dermatophagoides pteronyssinus and Dermatophagoides farinae ), grass pollen mix (Phleum pratense , Poa pratensis , Dactylis glomerata , Lolium perenne ,Festuca pratensis and Avena eliator ), grain pollen mix (Secale cereale and Triticum aestivum ), weed pollen mix (Artemisia vulgaris , Plantago lanceolate andAmbrosia artemisiifolia ), tree pollen mix (Alnus glutinosa , Corylus avellane , Betula verrucosa , andQuercus petraea ), molds (Alternaria alternata andAspergillus fumigatus ), and animal dander (cat and dog). Histamine (10 mg/mL of histamine phosphate) and 0.9% saline were used as positive and negative controls respectively. Weal 3 mm greater than the negative control was considered a positive reaction.