Hair Falling off 4 Years After Hair Transplantation (FUE) Procedure

The most likely reason your transplanted hair is falling out is Telogen Effluvium.  This is a temporary condition caused by something stressing the follicles and should abate once you are relieved of the stress.  

The other possible cause of this hair loss would be unlikely, but perhaps the grafts were harvested from donor hair which was located too high in the back of the scalp, in an area which was prone to the effects of DHT or other permanent hair loss factors.  If the only hair you are losing is the transplanted hair, then this is possibly the cause, although it would be difficult to determine.

This can be a frightening and confusing thing for patients to see. Depending on your age and stage of hair loss at the time of your surgery, there are a lot of possibilities for what could be going on. In most patients, 4 years after surgery what is usually seen are the native (non-transplanted) hairs falling out. That is a natural progression of hair loss. However, in some patients the genetics of hair loss is so strong that some of the hairs from the donor area were destined to fall out. Often times these are hairs that were taken from lower down on the back of the scalp, near the neck. Some patients have receding hair loss here (but it recedes UP the scalp there instead of BACK like on the hairline). Other medical issues could also be also have developed since your original surgery that can cause problems in the skin and thereby cause hairs to fall out (autoimmune conditions or hormonal imbalances). The first step would be to see your original surgeon or another experienced hair specialist to get proper guidance. Hope this helps!

I suggest you to see your hair specialist and have a general check up, and get your hormones checked as well.