Decking halls with boughs of holly and twinkling trees spreads yuletide cheer for many holiday celebrants. But amid the backdrop of nostalgic decor emerges a seasonal syndrome sabotaging merriment for some. Invisible allergens riding evergreens trigger classic respiratory and skin symptoms creating “Christmas tree syndrome” – the sad fate of developing runny noses, coughs or rashes instead of cozy comfort from the symbolic centerpiece. Culprits range from specific pollen species to generic irritants like mold, dust and pesticides. Real varieties pose more concerns with natural volatile oils and shedding pine needles. But cheap synthetic trees harbor other hazards after years