Hi. DD1 has very bad eczema and a proven houst dust mite allergy is the cause. She also has a nut allergy, so watch out for that. Anyway, you will find loads and loads of advice all over the place. 2 things helped me. One was asthma nurse (DD1 has asthma also, but this is easier controlled) Nurse explained that it is humidity which allows the mould to grow on their poo- this is the actual allergen, rather than the mites themselves. Therefore lowering humidity essential- can do this simply by airing the bed and opening the window. Second thing relates to the onerus (sp?) and impractical advice you will be given- damp dust every day, boil wash all bedding twice a week, hoover inside wardrobes etc etc. DD1s consultant (an immunologist) said that you will NEVER eliminate the mites, so it is pointless to wear yourself out and feel guilty about failing. Better pick the things you can do, and do them.
Sorry that's so long, just I feel mothers especially get made to feel guilty for not manging the impossible. There was some documentary on TV not long ago that did exactly that- made me furious. Good luck.