Shock loss in simple language can be explained as loss of natural hair (in the donor or the recipient area) after a hair restoration procedure is performed on a patient. The general cause of shock loss is trauma. The trauma experienced by the hairs can be of physical or chemical nature or even both. The mechanical or physical cause may be due to the surgery tools used to perform the hair transplant.
The way to avoid mechanical hair loss is to work with high magnification, to be able to spot the gaps clearly among existing rows of hair and to avoid transplanting in areas without gaps. The chemical reasons involve inflammatory reactions of the body due to the surgery. The body sees any operation as a sign of trauma and tries its best to counter the damage by signaling various immunity cells to the area of trauma. These inflammatory reactions affect the existing natural hairs that are weak. This traumatic loss of the non-transplanted hair is usually in and around the area of the fresh transplant in the recipient area and is less common in the donor area.
In a hair transplant surgery, hair taken from a permanent zone (usually from the back side of the head) is implanted on the bald patch of the head. In the target area where the new hair is implanted, the blood supply and nutrition may get temporarily hampered and competitive, which might be the cause of temporary hair fall of the existing hair that are already in the resting phase (Telogen phase). However, this “shock loss” of hair is only temporary and comes back after few months of the shed, post the surgery. If the patient has multiple miniature or fine hairs in the scalp, then these set of hairs do not fully re-grow after a shock loss episode. This is because these fine hairs are way too weak and thin to grow again. Shock loss usually occurs 2-3 months after the procedure.
The reason of the shock loss syndrome is not completely understood but the primary cause is the changes in blood supply, as described above. The chances of experiencing shock loss may significantly differ from surgeon to surgeon and the techniques that they employ. It is generally seen that shock loss is more of a common occurrence in women than in men. Also, larger hair transplant cases have more of shock losses than smaller cases do. Shock loss is not really specific to the type of the transplant procedure chosen (FUE or FUT).
Shock hair loss or shock loss is a phenomenon that should be discussed in detail with your transplant surgeon before you actually undergo the procedure. Though it is a rare occurrence but it occurs in about 5% of the transplant cases. Pre-operative hair maintenance that involves taking medications like Propecia or Regaine will help decrease the possibility of shock loss of existing hair.