Does sweating cause eczema flare?

Yes, too much sweating aggravates eczema symptoms. The mechanism of sweating is to regulate body temperature. When our body temperature rises, we get sweaty, when this sweat gets in contact with air it evaporates, cooling us down. As the sweat evaporates, the skin dries leaving behind a salty residue that can irritate eczema skin resulting in itching causing eczema flare.