Leavitt said Trump had asked her to share the diagnosis "in the effort of transparency."
'Pretty common'
Dr. Matt Heinz, an internist and hospitalist from Tucson, Arizona, told AFP that chronic venous insufficiency is "pretty common," especially in older adults. It results from vein valves becoming less effective.
"It comes with age, gravity, and obesity doesn't help if that's a condition that people suffer from. I know the president's been losing some weight, though, so I think that's probably a little better," he said.
The White House pressed home its message that the condition did not pose a serious risk to Trump, saying that "importantly, there was no evidence of deep vein thrombosis or arterial disease."
Trump had "normal cardiac structure and function, no signs of heart failure, renal impairment or systemic illness," added Leavitt.
Of the hand bruising issue, Leavitt said: "This is a well-known and benign side effect of aspirin therapy."
For months, however, the White House had previously dismissed questions about Trump's bruised hand, saying that it was purely down to handshaking.
The health of US presidents has always been closely watched, but with the White House seeing its two oldest ever occupants since 2017, the scrutiny is now heavier than ever.
Biden's health was a key issue in the 2024 election, and the then-president was forced to drop his campaign for a second term after a disastrous debate performance against Trump.
Republicans in the House of Representatives have issued subpoenas to several Biden aides, including his doctor, to get them to testify in an investigation into the Democrat's mental fitness.
Biden was diagnosed with aggressive prostate cancer in May.
As far as Trump was concerned, his condition was likely to be treated with compression socks, activity and maybe weight loss, rather than any "invasive" treatment such as prosthetic valves, Heinz said.
Swelling could indicate something more serious, such as heart issue,s "but I don't have that information."