Rubbing off scabs/crusts 4 days after FUE.

Hello,
The donor area after FUE, whether by hand or ARTAS, takes some time to heal.  Most patients heal atraumatically over a period of weeks.  As your hairs begin to grow, the donor area becomes harder to see.  Daily washes with mild soap can help keep the donor area clean.  If scabs form, mild soap and water can be helpful.  We use PRP in the donor area to facilitate healing as well.  
Best,
Anil Shah

In general most doctors have very specific post operative care instructions.  It is best you follow your doctor's recommendations. 

If a graft comes off for good, as in being lost from dislodgement, you would observe some bleeding. Since you did not observe any bleeding, it is likely that no graft has been lost. Keeping the grafted areas and scabs very moist from the time of surgery enables the easy removal of scabs with minimal trauma to the grafts.

It
sounds as if you were following the post op instructions and washing your hair/scalp
daily to remove the scabs.  By the end of
the 4th day the grafts are set in their new location and essentially
can’t be pulled out by rubbing or brushing. Most likely you have lost only the
hair shaft with some scabs.   If you have
any continuing concerns you should see your hair transplant physician for a
follow-up.

It's as simple as that!  In my experience the grafts are secured in place by the normal healing process by day 3.  I have tried several times to disrupt grafts from their bed by gently washing at 3 days and they do not move.  If viable grafts are dislodged there is bleeding from the site.  It's as simple as that!

I recommend patient follow post operative care very carefully.  It sounds like you are doing what is advised and since there wasn't any bleeding all your grafts are likely secure.

Generally I would recommend waiting 48-72 hours for first shampoo using a cup of room temperature water with shampoo mixed in applied gently. At 7-14 days normal shampooing can be resumed. This is true for the typical patient in my practice but you should confer with your own physician.

Most doctors recommend washing gently as soon as the next day, with scabs removed in about a week. Gently rubbing off the scabs at day 4 is a typical part of this, so I would be surprised if you removed any grafts at this point, especially if there was no evidence of trauma like bleeding. 

Many, if not most, surgeons advise their patients to begin shampooing gently as early as the next day and more aggressively as early as the 5th day. As long as you didn't pick at the scabs, and since you say there was no bleeding, it is unlikely that you lost any grafts.

WI generally recommend and if you washed it properly, there will be no crusts on it, even the very next day. Use of a sponge which we supply our patients, a surgical sponge to fill with soapy water and press on the recipient area daily. By repeating this daily, all crusts can be washed off without any fear of losing grafts. IF any crusts are present, use a Q tip and dip it into soapy water, and roll it on the crusts and that will lift them off without dislodging them, but never rub them, just roll the Q tip on the recipient crust. I like to see no evidence of any crusting in the recipient area and the crusts from the donor area gone in 7-10 days with daily washing.