The word issue has been used with various meanings since the Middle Ages. For most of that time, English speakers have talked about issues, but rarely have they had issues.
Issue derives from classical Latin exitus: “to go out.”
The noun issue can refer to the action of flowing out, as in the medical sense of “a discharge of blood or other matter from the body”:
Three days afterward there was an issue of pus through this opening.
An issue can be an exit, a place where something comes out:
The identity of its waters is shown by the re-appearance of light bodies at its issue that have been thrown into it above the place where it enters the mountains.
As a verb, issue means, “to exit” or “come out of”:
How to explain these expressions of frustration, contempt and downright hatred heard from audiences issuing from the theatre?
When Theseus was most enraged by his conviction that his wife had betrayed him, a deep, subliminal rumble would issue from beneath the auditorium, making the whole theatre shake.
As a noun, issue can mean children:
This amendment proved academic, as the abdicated King Edward VIII died without issue in 1972.
Some matter or question that is under discussion or in question is an issue:
The issue under discussion was not about victims or about pity, but rather about challenging oppression and discrimination.
The public is concerned with issues of all kinds:
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Issues are topics that are viewed differently by different people.
Problems are major and minor difficulties that must be overcome.
Problems are not controversial in the way that issues are. For example, the adoption of the Common Core Standards is an issue. Poor television reception is a problem.
Since the mid-1980s, the noun issue has been co-opted by many speakers as a word for what used to be referred to as a problem.
problem: a matter or situation regarded as unwelcome, harmful, or wrong and needing to be overcome; a difficulty.
Here are some examples that use issue where the word problem would be sufficient:
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I can sympathize with people who have an issue with dogs.
If you suspect that you need more help with your reception issues, just have a chat with your local antenna specialist.
Hairballs are a common issue with cats.
Is your Apple computer having issues playing sound from the built-in speakers?
I’ve noticed that people with contacts don’t have as much of an issue with onions.
Perhaps some speakers feel that issue sounds grander or more scientific than problem.
To be sure, there is some overlap between issues and problems. Climate change, for example, is both an issue and a problem. But when it comes to controlling hairballs and peeling onions, problem will suffice.