DOGMA - Doctrine taught by the Church to be believed by all the faithful as part of divine revelation.
and
DOCTRINE - Dogmas are those doctrines which the Church proposes for belief as formally revealed by God.
Does ANYONE else read this as saying the two are the same? Dogma is doctrine by divine revelation. Doctrine is dogma reveal by God. What is the difference??? Perhaps a better source should be used for the "official" definition because this sure doesn't do it.
Either way the Catholic Church has used its authority to demand adherence to whatever is declared doctrine/dogma by whatever method, by whoever is in the Magesteria office at the time, regardless of Scriptural confirmation.
If you quote the first sentences alone, many paragraphs that introduce distinct ideas would seem the same.
The difference is in the formality and the centrality of the proposed doctrine. A dogma is a doctrine that is proclaimed to be revealed by God to the Church. It is introduced as such, usually, by an Ecumenical Council, as something that has been believed by the Church everywhere at all times, even before it was proclaimed. It has a formal definition. For example, divinity of Christ is such dogma; in fact, the Creed is a succession of the dogmas of the Church.
A doctrine which is not a dogma usually is less precisely formulated, and refers to a question that not every Christian faces. For example, the use of contraception is not a matter for everyone, cannot be reduced to as simple paragraph (to explain the moral aspect of natural family planning, a related concept, requires several pages usually), and hopefully one day contraception would be looked upon as a barbaric practice that spread in 20c as a side effect of the collapse of the Protestant Reformation, and is now abhorred by all.
All doctrine, dogmatic or otherwise, is necessary for salvation, so the distinction is usually without a difference, especially for a non-Catholic.