Ruthie Davis plucked a shoe from a rack of candy-colored creations, her long lilac nails tracing a heel that was almost the height of her palm. It was the kind of stratospheric heel that has helped Ms. Davis make her name as a shoe designer.

Those heels, in high demand in the United States, are now piling up at her factory in Brazil, where shipments to the United States are paused because of President Trump’s sky-high tariffs.

Brazil seemed like a safe bet for a small business like hers, less expensive than manufacturing in Italy and more suited for a small-scale luxury business than China’s vast sneaker factories. But Mr. Trump’s decision last month to impose a 50 percent tariff on Brazil’s exports — among the highest he has placed on any country this year — has thrown that strategy into disarray. Ms. Davis has put off any more shipments, wary of the enormous tariff bill she would face when the goods crossed the U.S. border.

“The problem is, a 50 percent tariff for these smaller brands, we can’t absorb it, and we don’t have any flexibility to move our production,” she said. “We don’t have this huge budget and all this money sitting around.”

Even though her shoes retail for $500 to $1,000, Ms. Davis said it was hard to turn a profit. Her shoes are typically sold at a discount to that price. She pays a lot for shipping, including airfreighting her shoes in from abroad, as well as for marketing.

“Nobody needs a luxury shoe,” she said. “So I have to market the heck out of a shoe.” If tariffs stay at their current level, she said, she is not sure how long her business can hold on.