Can Hypothyroidism Cause Under Eye Bags?

Hypothyroidism can cause lower eyelid bags, although it is not a common presentation. It is more likely that you developed the bags independent of your thyroid condition. Insurance companies will only pay for upper eyelid hooding that obstructs peripheral vision - however, this must be demonstrated by a specific test in your Oculoplastic Surgeon's office. In addition, the insurance company usually requires photographs for proofs of substantial hooding - this will be reviewed by a doctor from the insurance company. I hope you find this helpful.

Even if it can be shown to be due to hypothyroidism, which I'm not sure it can, this condition would still considered "cosmetic," and as such I'd be very surprised if any insurance company would cover its treatment.

Caroleb37,
Yes, thyroid conditions absolutely affect one's appearance. Thyroid disorder, either hyper or hypo, changes the skin, hair, muscle, and bone. For some thyroid patients, they may have increased under eye bags with a tired appearance, or eyes which seem to pop out of their head. Generally, most surgeons performing eyelid surgery will evaluate for thyroid condition, in addition to allergies, prior to any cosmetic surgery. It is very difficult to determine, however, how much of one's appearance is specifically due to thyroid condition vs. normal aging, or other factors.
As far as I know, there isn't any medical necessity for surgical treatment of under eye bags or lower eyelid cosmetic surgery. Insurance may cover upper eyelid or eyebrow surgery, if your visual field is affected.
Speak with a surgeon performing eyelid surgery to help determine if cosmetic eyelid surgery is appropriate for you.