Sayyiduna Walid bin Uqbah (may Allah be pleased with him) said: When the Messenger of Allah (peace and blessings be upon him) conquered Makkah, the people of Makkah began bringing their children to him (peace and blessings be upon him), and he (peace and blessings be upon him) would pass his hand over their heads and supplicate for them. I too was brought to him (peace and blessings be upon him) while I was wearing khaluq (a kind of perfume), so he (peace and blessings be upon him) did not pass his hand over my head, nor did he touch me. Nothing prevented him (peace and blessings be upon him) from doing so except that my mother had perfumed me with khaluq, so he (peace and blessings be upon him) did not touch me only because of that khaluq.
Hadith Referenceالمعجم الكبير للطبراني / باب الواو / 18626