Hives and synthroid

[Jennac23]

I have a hypothyroidism, and was off meds for a couple of years. A few months ago, I tested 15 tsh and my dr started  me on 50 mcg levothyroxine.  After 8 weeks I retested and my tsh was 7, normal range being below 4. My dr increased my dosage again to 75mcg. Soon after this increase I started noticing hives. Hives cover my torso, thighs, buttocks, and they are large welts, extremely itchy.  I thought it was the levothyroxine so I switched to synthroid. This change had no effect. I saw an allergist and did a scratch test with everything coming back negative. I stopped taking meds and subsequently my tsh shot back up to 22.  Hives keep getting worse, especially waking up In the morning.  I found out I was pregnant and went to see endo, who immediately changed my dosage to 200 mcg synthroid, and no relief from hives.  I just switched to 200 mcg tirosint which has no fillers. It's been a week hives are not a severe but still occur.  How long until the synthroid is out if my body so I can find a reason for hives? I suffer daily and don't want to take too much Benadryl while pregnant but hives are unbearable.

[Lendi20]

I have the same problems! I have been struggling with chronic urticaria for nearly 2 years now. I have seen an allergist who tells me I have some allergies, but nothing to cause this sort of reaction and I have seen a dermatologist that FINALLY checked my thyroid antibodies (which were elevated) and sent me to an endocrinologist. I was diagnosed with Hashimoto's Thyroiditis and put on 25 mcg of Synthroid. Since I have been taking the Synthroid my hives have MAJORLY worsened. To the point where I am one giant welt. I don't see my Endo again until August so maybe 3 more weeks. I don't know if I can take it anymore! The rash/hives worsen during the night and early morning and then decrease theough the day, only to worsen again at night.

[Barb135]

That's a huge jump from 75 mcg Synthroid to 200 mcg.  Are you being tested for anything other than TSH?  You should also be getting tested for Free T3 and Free T4, along with the TSH.  If you have results for those, please post them and be sure to include reference ranges, since ranges vary lab to lab and have to come from your report.  There are a lot different doses between 75 mcg and 200 mcg and there's a good chance one of them might have been sufficient for you.

TSH is a pituitary hormone and fluctuates greatly, even intraday and it's affected by so many variables that it's just not sufficient to diagnose/treat a thyroid condition.

It takes T4 (levothyroxine) several weeks to completely clear the system, but if you were reacting to the fillers/binders in the pills, it shouldn't take that long for those to get out of your system.  It may take a while for the hives to clear, though.  Have you tried putting calamine lotion on the hives?  Check with your doctor to be sure it's okay to try it, since you're pregnant.