Can an Alarplasty Be Done Under Local Anasthesia?

Yes, limited alar base reduction (such as wedge excisions) can be done with an injection of numbing medicine in certain situations.

A large determinant of whether it's a good idea to do a procedure like this with only local anestesia is the patient's motivation and demeanor.

That depends on what you mean by an alarplasty. If it is just removing a small wedge of skin to narrow the alar base sure that can be done under local. If fine manipulations of the alar cartilages are required with shaping sutures and/or cartilage grafts I would not advise doing it under straight local anesthesia if you want a reliable result. More invasive rhinoplasty procedures with infractures etc. are actually safer when performed under general anesthesia. That is because if blood from the nasal area gets past the back nasal openings into the back of the mouth/throat in a sedated person the results can be disastrous with loss of airway control. In such cases general anesthesia is safer with a tube past the vocal cords, the patient fully asleep and some packing in the back of the mouth so no blood whatsoever can go down south.

I hope you realize that this format of posting questions and receiving answers lacks the face to face direct communication required for you to make an informed decision regarding your surgery.

My response to your question/post does not represent formal medical advice or constitute a doctor patient relationship. You need to consult with i.e. personally see a board certified plastic surgeon in order to receive a formal evaluation and develop a doctor patient relationship.