How can I repair this? Water leaking on staircase.

[Wherehasitgone]

Our bathroom had a leak and has caused this damaged to the wall on the stairs. Is there anyway to repair without having to completely repaint all of the hall/stairs and landing? TIA!!

Once it is fully dry, you can scrape off any loose material, apply a brush-on stain blocker, and repaint the damaged area.

The patch of new paint will show.

If you get a fair match to the old paint it will show less if you paint that entire wall, ceiling to skirting, and into the corners at each side.

Emulsion painting indoors is not very arduous.