Reaction to an allergen

• Sound of a sneeze
• 'Gesundheit' preceder
• "Gesundheit!" evoker
• Allergic reaction
• Dander reaction, perhaps
• Sneeze sound
• Blessing preceder?
• Blessing evoker
• "Bless you!" trigger

Wiktionary Word definitions in Wiktionary
interj. (alternative spelling of achoo English)