Help! Balding 5 month Frenchie

My 5 month old Frenchie is loosing his hair on the top of his head, throat and chest. He is currently on Noroclav 250g for an infected lump on his paw but the hair was looking a little thin before he started so we dont think the 2 are connected. He's mostly white and his skin is quite pink but he seems pinker since he started balding. Any ideas greatfully recieved...