Baby Harry Potter was protected from Voldemort by Old Magic. That protection stayed with him beyond Voldemort's attack.
This single-shot short triggered a surprising amount of discussion on the Caer Azkaban discussion group. I have no plans to continue the story, but a follow on chapter or two is not beyond the realms of possibility ... some time.
All fiction is derivative and fan fiction doubly so. I make no claim to own any part of any of the following, all I have done is an attempt to put together the elements in a novel fashion, using words and ideas like Lego ™ bricks.
There is no money involved – all I do is to share what I do for my own amusement.
It was two days after dropping baby Harry Potter off at his relative's home that it started.
Albus woke with what could only be described as a nappy rash. An hour later, the itching and burning had passed, but he had a series of bruises on his arms and legs; on top of that, he was hungry and couldn't seem to sate his appetite.
As time passed, Albus frequently found himself in sudden pain, suffering cuts and bruises that, no matter Poppy's salves and magic, refused to heal without scarring. His back looked like a Jackson Pollock abstract rendered in scar tissue and blood. He had lost weight and was tired all of the time.
While advancing age might account for his degenerating eyesight, it didn't account for the constant photophobia that made his eyes sore and watery.
On occasion, Albus had suffered spontaneous magical depletion - not dangerously so, but for some reason he would suddenly feel as though he had been casting multiple patronuses for hours.
It was August the second of the year 1991 when Albus collapsed during a meeting with his deputy head, Minerva Mcgonnagall. As the elder wizard collapsed, she could see massive bruises and contusions appearing on his face and arms, his already crooked nose suddenly spread across his face and three teeth were ejected from his mouth.
The headmaster was admitted to the infirmary within minutes. Every time he began to heal, there was another round of injuries, usually around seven in the morning and six in the evening.
On the morning of the first of September, Albus greeted the day with a heartfelt scream of agony, the fingers of both hands having been mangled, as though slammed in a door. At a little after ten in the morning, his jaw and nose were once more broken.
The students arrived and the sorting and the feast were presided over by the Deputy Head. Albus slowly recovered.
The headmaster was less than an hour out of the infirmary when he witnessed Gregory Goyle shove Harry Potter from behind and down a flight of stairs. The boy all but bounced, but Albus collapsed with multiple fractures and a bad concussion. The event was seen by Professor Flitwick, who immediately put two and two together.
Flitwick finally knew how little Harry Potter had survived that dreadful Halloween night, and incidentally, he wondered if Harry's second middle name should be Dorian.
1 - Jackson Pollock
An artist of the modern abstract impressionist school. Google the name to get an impression of Albus' back.
2 - Dorian
A reference to an undocumented second middle name (a part of the magic) - and to A Picture of Dorian Grey.