Praise be to Allah.
Wearing a wig comes under the heading of attaching hair, which is forbidden, and the one who does that is cursed, as al-Bukhaari (5477) narrated from Mu‘aawiyah ibn Abi Sufyaan (may Allah be pleased with him), that he took hold of a piece of hair that one of his guards was holding and said, as he was on the minbar: Where are your scholars? I heard the Messenger of Allah (peace and blessings of Allah be upon him) forbidding this kind of thing and saying: “The Children of Israel were only doomed when their women started to use such things.” And it was narrated from Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (blessings and peace of Allah be upon him) said: “Allah has cursed the woman who adds false hair and the woman who has this done, and the woman who tattoos and the women who has them done.”
The scholars of the Standing Committee for Issuing Fatwas were asked:
What is the ruling on a woman wearing a wig to beautify herself for her husband?
Both husband and wife should make themselves attractive to one another, in ways that the other likes, so as to strengthen their relationship, but this has to be within the limits of what is allowed in share‘ah, not by doing things that are prohibited. The use of wigs started among non-Muslim women, who were so well known for wearing them and adorning themselves with them that this became one of their distinguishing features. If a woman wears a wig and adorns herself with it, even if she does this for her husband, she is imitating the kaafir women, which the Prophet (peace and blessings of Allah be upon him) forbade: “Whoever imitates a people is one of them.” Wigs also come under the ruling about hair extensions, which is even more vehement in its prohibition: the Prophet (peace and blessings of Allah be upon him) forbade this practice and cursed the one who does it.
Fataawa al-Lajnah al-Daa’imah, 5/191.
It is permissible for a woman whose hair has fallen out to seek treatment, even if that is by having hair transplants, because this is not changing the creation of Allah; rather it is treatment to restore what Allah, may He be exalted, had created.
It says in a statement of the Islamic Fiqh Council belonging to the Organization of the Islamic Conference, during its eighteenth session which was held in Malaysia 24-29 Jumaada al-Aakhirah 1428 AH (9-14 July 2007 CE), regarding cosmetic surgery, and explaining what types of cosmetic surgery are permissible: rectifying accidental defects such as scars caused by burns, accidents, illness and otherwise, such as transplanting and patching skin; reconstructing breasts if they have been removed fully or partially; adjusting the size of the breasts if they are so large or so small that it will could lead to health problems; and hair transplants in the case of hair loss, especially for women. End quote.
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) was asked about a woman who had taken medicine that caused loss of the hair on her head, or most of it, and she did not want to use a wig because she believed it to be haraam. He replied:
With regard to using a wig in a case such as that which you have described, where the woman’s hair has fallen out in a case in which there is no hope of it growing back, we say that in such cases there is nothing wrong with wearing a wig, because in fact it is not done to enhance beauty; rather it is done to remove a defect. Based on that, it does not come under the heading of adding artificial hair or hair extensions, for which the Prophet (blessings and peace of Allah be upon him) cursed the one who does it. He cursed the one who attaches something to the hair and the one who asks for that to be done, and that refers to one who attaches something to her hair, but this woman in fact cannot be likened to the one who attaches something to her hair, because she does not want to enhance beauty or attached anything to her hair that Allah, may He be blessed and exalted, created for her. Rather she wants to remove a defect that has arisen, and there is nothing wrong with that, because it comes under the heading of removing a defect, not enhancing beauty. There is a difference between the two matters. End quote.
And Allah knows best.