Among the hundreds of refugee families waiting at the border, some had no passports.
Others would not go further until their husband, brother or son was granted a visa — which women and children are exempt from.
One woman was "sleeping sometimes on the ground, sometimes on a bus" for several days, she told AFP, waiting for her cousin to be issued a visa by the Egyptian consulate in the border city of Wadi Halfa.
She eventually crossed together with a few of her aunts, but "my cousin, he's still waiting," a month after fleeing their home in Khartoum, said the woman, who asked not to be identified.
Stuck in Wadi Halfa, "everything is overpriced because of war profiteers," said a Sudanese man who finally made it to Cairo after a two-week wait.
Others prefer to try their luck at another Egyptian consulate, in the Red Sea city of Port Sudan, more than 650 kilometers away from Wadi Halfa.
But they are not guaranteed relief there either. Youssef al-Bashir said he had been waiting "for five days" along with hundreds of others to submit his application.
Since fighting began on April 15 between the forces of two rival generals, more than 132,000 refugees have arrived in Egypt, the International Organization for Migration said on Wednesday.
More than a million others have been displaced internally in Sudan, and across the borders of other countries.
Many of those who could not flee have hunkered down in their homes without basic supplies.
For those who make it across the border to Egypt, the Egyptian Red Crescent provides care for the sick and hands out water and biscuits.
Our second country
Unlike in other neighboring countries that have been taking in Sudanese refugees, humanitarian operations in Egypt are limited.
Cairo refuses to set up refugee camps and instead says the new arrivals are given the right to work and move freely.
President Abdel Fattah al-Sisi has repeatedly said his country is hosting "not war refugees" but "guests."
Sudanese who cross into Egypt's south must then buy a bus ticket to take them to the nearest major city, Aswan, around 200 kilometers north of the border.
They are greeted there by volunteers who offer a hot meal -- the first for many since embarking on the perilous desert journey.
"We serve three meals a day. For lunch there is chicken, pasta and beans," said Mansour Jomaa, one of about 60 volunteers.
"We also deliver meals to a dozen houses," where "sometimes eight families are crammed together," he told AFP.
More than four million Sudanese were living in Egypt before the war, according to the United Nations. The neighboring countries share the Arabic language, cultural ties, and fabled history dating back to the Pharaonic era.
Egypt was an "obvious" destination, said Walid Ahmed, a refugee who left Wadi Halfa and headed north. "It's our second country."
"The number of people waiting to cross into Egypt is increasing," said Carlos Cruz, head of the IOM mission in Egypt.
The United Nations agency needs $19.9 million to provide them with "water, food, hygiene kits and medicines", specifically for diabetes and other chronic illnesses, he told AFP.
"In the longer term, there will also be other needs including education and livelihoods," Cruz added.
Many of the Sudanese refugees AFP spoke to believe it would take a long time, perhaps decades, before they can return home.
They carried with them their savings in dollars, a precious asset in Egypt where an economic downturn has boosted the purchasing power of foreign currency.