Why does my toddler smell like scrambled eggs when he gets sweaty

This is an odd question but does anyone else’s toddlers have an odd smell when they sweat? Particularly on their head lol my sons 2.5 years old, I’m currently 6 months pregnant so maybe it’s a smell aversion idk but when he gets sweaty or starts getting clammy after he’s been running around a lot, his head literally smells like fresh scrambled eggs lol