White paint like marks on external walls

Hi all,

We recently rebuilt our redbrick garden wall.
I've noticed a lot of white paint like marks on it almost like someone got a paint brush dipped in white paint and ran it across it. Its very prominent in some parts and non existent in others. My husband said its lime seeping out of the bricks or something like that.
Its worse after rainfall.

Does this eventually go? The wall was put up about 18 months ago.

Any thoughts on what, if anything gets rid of it?

Thanks

It's probably efflorescence

Janey!!! No quick fix solution so. Darn!