Understand from lovesnow she meant what 小乔 had explain "a kind of symptom, when someone is "shanghuo", his lips will easily get dry, sometimes the teethbridge will get inflammatory or shanghuo. So the term we use in the case is actually "heaty". For eg, I get heaty when I consume too much chocolate. Do this explanation resolve the mystery of "上火"? Thanks to all... Cheers!

so how to say "shanghuo"in english?

no, no, she really want to ask is: 上火 she mentioned is a kind of symptom, when someone is "shanghuo", his lips will easily get dry, sometimes the teethbridge will get inflammatory. he is also uncomfortable physically.

yes, agree with Bill, and on top of that, i think 夏天 is an expression for adverse whether or conditions, not necessary referring to the whether. And 上火 also means irritated, grouchy, temperamental, not necessarily talking about anger. so i would say "adverse conditions makes one easily irritable"

"To add fuel to the fire", When there are problems this is used to describe a person causing more problems.