Can you have both underlying adrenal insufficiency and thyroid disease, while treated with levoxyl (thyroxine)?

Yes.: Both adrenal insufficiency and hypothyroidism can be caused by autoimmunity, where the immune system makes antibodies that target someone's own proteins. It is possible for someone with one autoimmune condition to develop another. Ask your doctor if this could be true for you.

Yes you can: And it will fall under the condition called autoimmune polyglandular syndrome type 2 (aps 2), also called schmidt disease. Risk of autoimmune diabetes is also higher in type 2 ( versus type 1, much rarer here in the us).

Presumably : If you're already on Levoxyl (thyroxine) then i presume you already have thyroid disease. Those with autoimmune adrenal insuffiency tend to also get thyroiditis. Another combination of adrenal and thyroid dysfunction can also occur at the level of the pituitary gland which is not usually autoimmune.

Adrenal: Thyroid disorders are usually caused by autoimmune disease. This too causes adrenal insufficiency. Yes -- they can run together.