Although you notice no consistency in the pattern of breakout as you stated in the occurences happening in different climates and environments, there is one consistency to consider. In the different climates and environments I can make the assumption that you are showering, bathing or cleansing your skin. Therefore, the consistency may be found in the water used to cleanse your skin or in the product used to cleanse your skin or wash your hair. Chlorine or flouride in treated water is a major eczema irritant. This may be something that you need to consider and address by such methods as a water filtration system.
You've stated that you've tried many different forms of treatment with no successful results. As long as the eczema irritant is continuously reintroduced into your system then any of your efforts to heal will remain short term successes.
With the last breakout, can you remember what you did that day prior to the flareup?