Muhammad bin Ishaq (may Allah have mercy on him) narrates from Fatimah bint al-Mundhir, and she from Sayyidah Asma' bint Abi Bakr (may Allah be pleased with her), that she said: I heard the Messenger of Allah (peace and blessings be upon him) while a woman was asking him. She said: O Messenger of Allah! I married off my daughter, and this illness - smallpox or measles - afflicted her, as a result of which her hair fell out. Then she recovered, and her husband has been pressing us about her, while there is no hair on her head. So may we put something on her head with which to make her look beautiful? He (peace and blessings be upon him) said: "Allah curse the woman who attaches hair extensions and the woman who has them attached."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 20719