I have this horrible smell in my bathroom. It started about 3 weeks ago. It smells like rotten onions or really really bad BO. The smell never goes away no matter how much I clean. I have had a plumber come out and check the pea traps but everything is in working order. They have no idea what could be causing this smell. It is more predominant in the shower area. Does anyone know what this could be? Please help.

Showers, tubs and lavatories can build up rotting hair matted in with grease that can produce bad odors. Did the plumber snake out the drain line?
. Try this for the smell. Tonight before bedtine Take a 1/2 gallon of bleach and pour it down the drain and let set over night. Next morning ,(and this is important) flush out the drain with two large pans of boiling water to loosen the grease and flush the mess out. The bleach will make the hair slippery and began to dissolve it and the hot water will melt the grease and flush the mess away. Let me know if it helps. Tom