The thyroid is up against the neck, so trauma to the neck can affect the thyroid. I have adrenal fatigue and I take iodine. I have mild AF, though (high cortisol). If you have severe AF, you'd definately need to support the adrenals before taking anything for the thyroid. Kelp is known to be contaminated with arsenic. If you're going that route, make sure that it is contaminate free.
Celantro and chorella can help detox mercury. Iodine will displace and chelate mercury, arsenic, fluoride and bromide. You need to support the liver to help it detox that stuff out. ALA, milk thistle and NAC are helpful in this regard. I take NAC to support my liver and I've stopped getting the bromide acne. When I forget to take it, I get those awful painful red breakouts.