Strange yellow marks that move as I paint on them

[DW97]

I have recently noticed yellow stains on my wall that seem to move whenever I use a damp seal paint on them. Using the paint seems to have also made it worse. Can anyone help with what this is?

 

[RandomGrinch]

Damp seal will stop the moisture coming through where you have painted it. If the damp is still entering the wall, it will still find its way out - as it can't come out through the new paint, it will make its way around it.
You need to find the cause of the damp in the first place.

 

[securespark]

Is this an external wall?

If so, go outside and look for signs of damp. Leaking gutters or drains are often the culprit.

 

[noseall]

Can anyone help with what this is?

Distemper.

 

[DW97]

Thank you all for your replies, this is an internal wall which is shared with my bathroom/shower. I think there could be a sealant issue on my bath so going to reseal it tomorrow and see if that helps