The mechanism and properties of mass loss are poorly known for Ap stars. Present upper limits on the mass loss rate are of 10−10 M⊙yr−1, a value which does not permit any element separation. Abundance maps could be a very powerful tool to constrain the mass loss rate and the wind geometry of Ap stars, as surface abundances are sensitive to rates as small as 10−15 M⊙yr−1. We here propose a diffusion-mass loss model for 53 Cam and compute abundance distributions in the photosphere of 53 Cam. The mass loss geometry is determined from the Ca II K line profile and its time variation. We obtain that the diffusion-mass loss model explains many spectral features of 53 Cam, both in the UV and visible domains.