Atopic status
This was assessed by skin prick test (SPT) using a panel of 20 common
inhalant allergens, including pollens, house dust mites, molds, and
animal dander, and 27 common food allergens including animal, fruit, and
vegetable allergens (ALK, Madrid, Spain). Histamine hydrochloride (10
mg/ml) and phenolated glycerol saline were used as positive and negative
controls, respectively. Patients were requested to stop taking any
antihistamine medication at least 8 days before undergoing SPT. A
positive SPT response was defined as a wheal diameter of 3 mm or larger
to at least one of these allergens; patients developing such a wheal
were considered atopic.