Upvote:2
La polizia del Stato (who deals with residence permit) states :
The same facilitated procedure is granted to foreigners who have submitted their application for their first residence permits for employment, self-employment, or family reunification, provided that:
- they leave and re-enter Italy through any Italian external border crossing point (cicular letter 11th March 2009);
- they show their passport or other equivalent travel document, along with the entry visa specifying the reasons of their stay (employment, self-employment, or family reunification ) and the receipt issued by Italian Post offices (Poste Italiane S.p.A.);
- they do not transit through other Schengen countries, as this is not allowed.
Now, leaving for 7-8 months, will likely make it extremely suspicious on re-entry.
This is made for small temporary trips, you may have issues at the border, as a residence permit is made for residence.
A more than a few-weeks absence will raise eyebrows, and maybe prevent eventual renewal or even lead to pure and simple revocation, I can't find for Italy but usually 6 months out of country will invalidate your residence permit