How do I get rid of exzema for once and for all? Triamcinolone acetonide cream helps it go away but it comes back

Difficult... It can be difficult to completely eradicate eczema but some measures that can decrease exacerbations include avoiding triggers that you are known to be allergic to, using mild soaps and detergents, frequent moisturizing with lotion (especially after bathing), etc. Use the triamcinolone cream on the affected area once the rash occurs until the area heals. See a skin doctor if it is worsening.