Starting from article 5. It seems that any such state of emergency can last up to 12 months and be extended for 12 more months. The current state of emergency is going to last until the end of July, and there are discussions about extending it.
That's a regular law, not part of the constitution, article 77 of the constitution provides further rules:
Apparently, article 77 describes 2 deadlines: 5 days for the parliament to vote on the decrees and 60 days for the laws to be finalized.
I think that the crux of the issue is: whatever is inside those "decreto legge/dpcm", it has to be approved by parliament... There have been multiple such decrees, and the only controversial point is for how long can a parliament decision be delayed (in theory only for up to 5 days, but I'm starting to get lost in details).
Due to how many decrees have been created, I'd need to check for when each one of them has been (or is being planned to be) voted on
Most of them, were, IIRC, only "reported to" parliament. After reopening on May 4th, some of them were voted.
I admit I worded my post poorly: a state of emergency exists, but limiting constitutional rights is, AFAICS, only permitted through law.
"DPCM" are mere administrative acts, and a few people expert in the judicial system have raised objections about their use in this way (including the head of the constitutional court). In particular, the debate is whether they can or can't limit constitutional rights.
There's no such thing as a state of emergency, only the state of war. Anything else needs to go through the parliament, directly or indirectly.
By indirectly I mean something akin to the USA executive order, but agreed upon the cabinet, not the PM, then countersigned by the President, who can veto it. Then it lasts 60 days and must be confirmed by the parliament, or becomes void.
Keep in mind the constitution was written right after WW2, so the writers were carrying the scars of "emergency measures" going into dictatorship.
There are a few things that can be done by the health ministry, but nothing as big as a country wide lockdown.