Jérémy Doku has given the fullest account yet of the frightening illness that derailed his World Cup, and it comes with a detail that raises eyebrows well beyond the medical tent: the Belgium winger says the treatment he needed included cortisone, a substance on the World Anti-Doping Agency's prohibited list.

"I could cry from the pain," Doku said of the days when his condition was at its worst, according to ONE, which reported the confession from the Manchester City forward. He described being administered cortisone to manage the crisis, medication that can trigger a positive doping test unless specifically cleared for use.

That clearance came through, ONE reports: FIFA's anti-doping process granted Doku a Therapeutic Use Exemption, the formal mechanism that allows athletes to take an otherwise banned drug for a genuine medical need without breaching the rules. Without it, the same treatment could have opened him up to a doping case rather than a sympathetic headline.

The saga began in the best possible way, with Doku starting Belgium's World Cup opener against Egypt and playing until the 86th minute of a 1-1 draw. It was afterwards that his body started to turn on him: a cough that would not shift developed into something far more serious.

Multiple outlets, including ESPN and OneFootball, have separately reported that Doku's condition escalated to the point where he was coughing blood and struggling to breathe, with tests eventually showing fluid in his lungs. He required an emergency hospital visit in the middle of the night to get it under control.

The illness cost him Belgium's second group game, against Iran, for which he was ruled out entirely. Belgium's medical staff and FIFA's doctors worked through the tournament to manage a player who, by his own description, was in some of the worst physical distress of his career.

There was a parallel, personal drama unfolding at the same time. While Doku was being treated, he learned that his wife had gone into labour weeks before her due date. He left the Belgium camp and flew home for the birth of his first child, a son the couple named Praise, before rejoining the squad.

Cortisone is effective at calming acute inflammation, but it is not without cost to an elite athlete: it can weaken muscles and tendons and complicate a quick return to peak physical condition. Doku never fully recaptured his sharpest form for the rest of the tournament, a knock-on effect of both the illness and its treatment.

He did make it back for Belgium's final group match, and the Red Devils advanced through the group stage before their World Cup run ended in the quarter-finals, where they were beaten by Spain.

The episode leaves Doku with an unusual footnote to a World Cup that also brought him fatherhood: a legitimately treated illness that, on paper, involved a banned substance, resolved only because the paperwork with FIFA's doctors was done correctly and in time.