A person sneezed in his presence and he said to him: May Allah have mercy upon you. And he then sneezed for the second time and Messenger of Allah ﷺ said to him: He is suffering from cold (and no response is necessary).
أَنَّهُ سَمِعَ النَّبِيَّ ﷺ وَعَطَسَ رَجُلٌ عِنْدَهُ فَقَالَ لَهُ يَرْحَمُكَ اللَّهُ ثُمَّ عَطَسَ أُخْرَى فَقَالَ لَهُ رَسُولُ اللَّهِ ﷺ الرَّجُلُ مَزْكُومٌ