What is the Main Cause for Areola Necrosis (Superficial Kind)?

The cause is (pretty much always) insufficient blood supply to nourish the areolar tissues. The cause of the insufficiency can be smoking, large implants placed at the same time, overdissection without allowing enough preservation of areolar blood supply, too tight compression by garments, and others.

All the best. 

I am guessing that you mean blistering with secondary healing as "superficial necrosis."  Most of us think of "regular" necrosis as a full thickness loss of areola or the most severe where the whole nipple/areola is lost.  It is possible to get some blistering as a reaction to the suture material, mostly the synthetics.  Necrosis is due to insufficient circulation, whether from reduced circulation coming in from the surrounding tissue, a closure that is too tight, the effect of nicotine on blood vessel constriction, of even a burn from the cautery used to stop bleeding or possibly dissection by the surgeon.  I also saw it once in a woman that was allergic to triple antibiotic ointment.  It started with itching but turned into blistering.