What kind of side effects are possible with hair transplant surgery?

Hair transplantation is a safe procedure that is performed thousands of times per year under local anesthesia and minimal sedation.  This eliminates the risk posed by general anesthesia required for many other cosmetic procedures (rhinoplasty, rhytidectomy, etc). The procedure itself has over a 90% success rate (very high). However, it is a surgical procedure with some risk, so this is a topic I discuss with every potential hair transplant candidate. I break up the risks into the following categories:

General Surgical Risk: Any surgical procedure with trauma to the skin will result in some form of scarring, including the risk of hypertrophic or keloid scar formation; bleeding; sensation loss or change that may be permanent; adverse effects associated with local anesthetic administration, including major systemic side effects like cardiac arrest or neurological impairment; infection. These are all <1% risks, but must be discussed.

Hair Transplant Risks

Short Term (first 3 weeks): Crusting, bleeding, oozing, infection, shock loss, transplanted hair loss

Long Term: There is a possibility that the implanted grafts fail (hair follicle death), leading to poor cosmetic outcome due to patchy or lack of hair growth, an unnatural appearance, including an unnatural hairline. This may result in the need for subsequent hair transplant procedures to correct. Scarring of the donor area, regardless of technique used (FUT or FUE), will lead to evidence of the procedure if you ever decide to shave your head. Failure to continue maintenance medical therapy may lead to further hair loss surrounding the area of transplanted hair leading to an unnatural appearance. Telogen effluvium, or shock loss, can occur following transplantation, where untouched hair falls out. This is a temporary condition with regrowth expected within 6 months, however, in rare situations, this may lead to permanent thinning of the region.