Assalaamu alaikum,
My questions are mainly related to my alopecia. I cant seem to get a clear cut answer, but before i do anything i want to be sure that im islamically correct in what I do.
1) Can i shave my whole head (if my condition gets worse & unmanegable ) on health grounds ?
2) Am i allowed to get my patches shaved by a barber who is most likely going to be a male who i dont know who specialises in alopecia ?
3) Can i wear a wig ? Ive mixed answers on this, so i dont know whats right ? I have bought some extensions, but ive read somewhere these are haram..so ive not used them yet.
If any of these can be clarified i would be grateful. thanks for your help.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

The scholars are of the view that it is disliked for a woman to shave her head; this was stated by Ibn Qudaamah from the Hanbali School of jurisprudence, and Shihaab Ad-Deen Ar-Ramli from the Shaafi’i School of jurisprudence.

For instance, Ar-Ramli said: “Some scholars made an exception for the dislikeability of shaving the head for a woman if she is harmed in her head and this harm cannot be removed except by shaving her hair in order to treat acne and the like.”

Moreover, Al-Buhooti from the Hanbali School of jurisprudence, said: “It is disliked for her (a woman) to shave her head or cut it without a sound reason, because Al-Khallaal reported from Qataadah from ‘Ikrimah who said: “The Prophet prohibited for a woman to shave her head.”, and if there is a sound reason like the ulcers (of the scalp), then it is not disliked. However, it is forbidden for her to shave her head when a calamity befalls her, like her slapping her cheeks and tearing her garments.” Based on this, a woman shaving her head is not disliked when there is a necessity.

As regards a woman having her head shaven by a non-Mahram man, then this is not permissible as he is not permitted to touch any part of her body. At-Tabaraani reported that Ma’qil Ibn Yasaar narrated that the Prophet said: "If one of you were to be stabbed in the head with an iron needle, it would be better for him than touching a woman whom he is not permitted to touch."

However, if there is no other female barber and it is a necessity for her to shave her head as an indispensable treatment, then it becomes permissible for her to shave her head by this male barber. The jurists stated that looking at a non-Mahram woman and touching her are permissible for cupping and venesection and for treatment, and they also stated that a husband or a Mahram should be present with her.

In regard to wearing a wig, it is permissible according to the most preponderant opinion provided some conditions are met. These conditions are clarified in Fatwa 90912, so please refer to them. 

Concerning joining the hair, it is forbidden; in this regard you may refer to Fataawa 82883 and 87969.

Allaah Knows best.