Is this damp?

[Mumoftwokids]

Here’s a couple of pictures and I’m wondering if this is damp? The same wall in the interior is showing no signs of damp eg mold or dark walls. I’m wondering if I should get a professional to look at it (-who?!) anyone know?

It's just salts, brush them off with a dry brush.

Thanks Scampuss. Sadly it has solidified, not a brush off job :-(

Might just need a stiffer brush or gently use a wire brush.